Rathlin Bird Report 2021-2022

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After last year’s hiatus (did you miss us?!), normal service has resumed and the Rathlin Bird Report is BACK!

Here you’ll find details for all the bird species recorded on Rathlin in 2022, plus notable sightings and occurrences from 2021. Although we really had intended to keep it brief this time, we actually found there was more than ever to write about! So we’ve also included special sections on bird flu reaching the seabird colony, the island’s secretive wintering flock of Greenland White-fronted Geese, an in-depth investigation into an intriguing Yellow Wagtail, and our experiences of seawatching from various parts of the island.

Click here for the full report (15 MB)

And if you’re eager to read even more about the birds of Rathlin, check out our four previous bird reports:

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We’re dedicated to making high quality resources that showcase and document Rathlin’s natural history, and we’re keen that these are freely available to anyone who is interested in the island and its wildlife. If our work has been useful to you, please consider supporting us with a donation. This is easy to do at our ‘Buy me a coffee‘ page. We’ve lots of ideas for future Rathlin wildlife projects and this will help make them happen. https://www.buymeacoffee.com/Stickybeak

Rathlin mothing review for 2022: 30 new species and an accidental moth trap

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Last year we gathered together everything we knew about the moths and butterflies of Rathlin into a big report, covering our first four years of recording 2017-2020 – you can find this here. Since then, we have continued our learning and recording of the island’s Lepidoptera, and 2022 has certainly produced a few interesting surprises. In August we wrote a brief post about three of the headline finds of the year – Striped Hawkmoth, Green Hairstreak and Holly Blue – so here we will attempt to review our other discoveries of 2022.

The biggest bobby dazzlers of the year: Striped Hawkmoth (left) and Green Hairstreak

First, a bit about our recording effort in 2022. Up to 2020, the majority of our recording was based around the western end of the island, then having been away from Rathlin in spring and summer 2021 (i.e. the main part of that year’s mothing season), 2022 brought us a new opportunity to spend more time focusing on the lower end. We had high hopes that the differences in climate and habitat might translate to noticeable differences in the moth community… and ideally a swag of new species for the Rathlin list!

In 2022 we recorded more than 9000 individual moths and butterflies of 351 species (plus 5 other moth taxa) on Rathlin by light trapping and field recording by day and at night. In previous years we have recorded between 272 and 358 species per year, so 2022 was our second richest year by this measure.

During 2022, we seem to have been a bit lazy on the trapping front, only accumulating 61 trap nights (compared with about twice as many as this in 2020). This is partly down to having only one easy site for the Robinson trap that fit the criteria of being nearby, away from competing street lights and not bothering anybody. As a consequence, on a run of good nights we more often deployed only the LED Heath trap on its own instead of being able to run two traps every night. Despite less trap action, by making a steady effort in field recording through the year as well, we made records on a total of 196 dates, which is actually considerably more than in 2020 (168 dates). By the end of 2022, our total number of records (2,700) exceeded all other years except 2020 (that really was our most obsessive year).

We also exploited a novel mothing resource in 2022 that is intermediate between field recording and light trapping (although really a lot more like the latter)  – the bright lights of the coastguard station. More about this later!

Our Lepidoptera recording efforts in 2022 have bagged 30 new species for the Rathlin list –  not a shabby result at all, especially considering it perhaps ought to be getting harder for us to find new species by now. We also got to meet a further four species that we had never seen on Rathlin, although we knew they had been recorded here historically.

This table summarises the number of Lepidoptera species that have been recorded on Rathlin, including the number of species recorded for the first time each year 2017-2022, and the overall totals. For more context on past recording done by us and others refer to Moths and Butterflies of Rathlin Island.
* In 2021, unlike all the other years, there was no recording on the island during spring and summer, but still two new species were added during the winter and autumn of that year.
& Includes one previously unrecorded species of micro-moth identified from photos taken in 2020.

A baffling butterfly bonanza

The biggest surprise was probably finding not one but TWO new butterflies for the island list – Green Hairstreak and Holly Blue – and that neither were species that we had particularly expected to see anytime soon. Small Heath, recorded only once in 2020, failed to show itself this year, but we managed to see all the other 14 species on the island list. Increased observation around the lower end this year revealed another small colony of Speckled Wood with several sightings of this locally elusive species along Church Brae, as well as a large increase in records of Small White and Large White, which thrive in the brassica-rich scrub and gardens of the harbour area. There remain two species on the island list that have been recorded historically but that we have never seen here – Dark Green Fritillary and Clouded Yellow.

New moths seen in 2022

Looking back on the year’s mothing, there were numerous notable and interesting finds – too many to cover here. Instead we’ll just focus mainly on those species that were new for Rathlin in 2022.

Early in the year we realised the all-night bright lights of the coastguard station had great pulling power for moths (and a variety of other invertebrates), so we got into the habit of regular patrols to check the walls around the lights. This paid off on the night of 14th March when we found Diurnea fagella on the walls – our first new species of the year, and also the first of 5 new species that we would record only by this method.

An accidental moth trap: the multiple bright external lights of the coastguard station shine out from the darkened hillside above the harbour, attracting moths like Diurnea fagella (right) from the surrounding scrub and potentially also from much further afield. Overall we recorded 105 moth species on these walls in 2022 (but who knows how many were snaffled from the walls by hungry birds before we saw them).

The next flurry of new species came in late April, with Elachista rufocinerea, Esperia sulphurella, Brindled Pug and Pale Pinion all recorded in the last week of the month. In mid-May we encountered several more new micros along the roadsides – Elachista apicipunctella became the 7th species of this genus recorded on Rathlin, then Phyllonorhycter nigrescentella was the first of what would be three new species recorded on the wing along Church Brae this year. Then came our first Light Brown Apple Moth, a non-native but now common and widespread species. We had numerous further sightings of Light Brown Apple Moth during 2022, and it seems perplexing that we had not encountered it on Rathlin previously – perhaps this species only occurs at the island’s lower end, or it has only very recently colonised Rathlin.

June brought several macro-moth highlights, starting with a flighty Silver Hook that required a frantic chase across heath and bog to confirm its identity. Then there were a couple more nice surprises – the first Dark Brocade recorded on Rathlin for more than a decade appeared on the coastguard station walls, and the island’s first ever Drinker came to our moth trap at the chapel. Finally, the month’s mothing culminated in our adventure with a much hoped-for Striped Hawkmoth.

As the summer ramped up, the 9th July delivered 3 previously unrecorded species in a single day – Brindled Plume, Monochroa tenebrella, and a Spilonota laricana/ocellana (which can’t be identified with certainty, but we strongly suspect was S. laricana). A busy second half of the month produced frustrating glimpses of Scallop Shell and Holly Blue, both eluding the camera, and Bryotropha domestica, spotted in a friend’s doorway, was also new for Rathlin. The moth trap also scored 3 island firsts in the form of Fan-foot, a beautiful and unexpected Four-spotted Footman, and a migrant Scarce Bordered Straw.

August had fruitful spells at the beginning and end of the month, resulting in 5 completely new species: Argyresthia goerdartella, Epinotia nisella, Barred Chestnut, Copper Underwing, and the leafmines of Stigmella tityrella on beech. The month also brought a further 3 species known from historic records but not seen here for many years: Annulet, Double Lobed, and Setaceous Hebrew Character.

Our only find during a relatively quiet autumn was pointed out to us on Twitter, after we mistakenly declared finding a Yellow-lined Quaker feeding at Ivy flowers. Luckily David Walsh was kind enough to suggest that it was actually a Brick, and the thrill of unexpectedly getting another new species in the bag soon helped us get over the embarrassment of not realising its true identity ourselves.

In December our mothing year ended much as it began, with a new species observed on the walls of the coastguard station. This time it was a Mottled Umber, a species likely overlooked in previous years due to its very late flight season. Then while sorting through past records and photos, we managed to squeeze in one more new species by finally identifying a mystery micro-moth photographed back in 2020. This was a puzzling creature, appearing similar to the more familiar members of the Adelidae, and yet looked nothing like any of the illustrations in our trusty bible field guide to micro-moths. But after trawling images online we at last stumbled on a match – a male Nemophora minimella, whose extraordinary large and highly distinctive eyes inexplicably don’t merit any mention in the field guide.

Other notable mothy findings of 2022

As well as extending the Rathlin species list, during 2022 we made numerous other observations that add to or update the information we included in Moths and Butterflies of Rathlin Island in 2021.

Many species with very few prior records (often only one) were sighted again in 2022, some multiple times which tempts us to think that they might be more common in the lower end of the island where we spent more time searching this year. For us, the standout species in this category is Coxcomb Prominent, previously known on Rathlin from only single records in 2019 and 2020 at the west end of the island. During June-July 2022 we encountered adult Coxcomb Prominents on 7 dates (both in light traps and on the coastguard station walls), and then in August-September we had the great pleasure of observing a caterpillar over a period of 15 days, slowly and very neatly devouring cherry leaves one at a time.

The Coxcomb Prominent is striking enough to see as an adult, but really something else as a caterpillar

In terms of Rathlin specialities, we were able to confirm the occurrence of Lempke’s Gold Spot at the lower end of the island, as further evidence that this species has a well established population on Rathlin, despite still being the only Irish location for this species.

Similarly we added records from new sites of scarce species Caryocolum vicinella, Agonopterix subpropinquella, Square-spot Dart, Bordered Grey, and Netted Pug, which we also found as a caterpillar for the first time, feeding on Sea Campion just west of the harbour. We didn’t manage to record some of Rathlin’s other most notable species such as Chestnut-coloured Carpet or Dotted Carpet, but we did not target any likely habitat for these species.

Netted Pug caterpillars munching on Sea Campion. This clump was also hosting many larvae of a another Rathlin speciality, the 24-spot Ladybird, and between them there was almost nothing left a few weeks later.

Although it wasn’t a brilliant year for migrants overall, as well as the Striped Hawkmoth and Scarce Bordered Straw already mentioned above, we observed a notable influx of Rush Veneers from late August into early September, and we were glad to see several Hummingbird Hawkmoths, once again attracted to the the profusion of Red Valerian growing around the harbour.

Also noticeable in 2022 was the abundance of Lesser Broad-bordered Yellow Underwings, with the number recorded being far higher than in previous years.

And one final thing that surprised us in 2022 was repeatedly finding Bright-line Bright-eye caterpillars on the beach in September, in many cases making an ill-advised journey across the open sand towards the sea. Having seen the adults very frequently, it was hard to believe we had never encountered a caterpillar before, although it is possible they were also particularly abundant this year on large swathes of their foodplant (orache) growing at the back of the beach this year.  

Phew! If you made it this far, thanks for reading and let’s hope 2023 is just as mothtacular.

Hold your horses, pup season 2022 is not over yet!

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Pup number 109 has arrived on Rathlin!

We just KNEW that as soon as we declared our 2022 pup total, some tardy little pupsqueak would appear on the scene! It’s now 17 days after we last added a brand new pup, and until today, all we’ve seen otherwise is empty beaches. In fact, only 4 days ago we were looking at bare rocks in the exact space that’s now occupied by the 109th pup of 2022. Will there be more??? Our Rathlin pup count continues… watch this space for the final total.

Mum and pup were initially passed out peacefully, until a male came galumphing along and settled on a rock far too close for comfort. So mum positioned her body between the interloper and her precious pup, and the wee one happily took the opportunity for a feed.

UPDATE 2nd Jan 2023: with no more new pups appearing since the above latecomer, hopefully we are now safe to declare that our 2022 pup season total is 109 pups.

Clifftop pup-watching and Rathlin’s Grey Seal pupulation in 2022

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By six weeks into this year’s prolific pup-time we had counted 91 pups, and they kept on coming!

As summer draws to a close on Rathlin, a wildlife-watcher can feel a certain melancholy to see the cliffs emptying of seabirds as the last of the year’s fledglings make their way out to the open sea, but the changing season means another exciting breeding event is about to kick off on the beaches below – Grey Seal pupping season.

Two species of seal occur on Rathlin – Harbour or Common Seal, and Grey Seal – and you can see both here throughout the year, swimming close to shore or resting on the beaches, sharing many of the same haul-out sites.

Their names aren’t much help tell our two seal species apart – both are grey, and on Rathlin both can be found in the harbour and both are common! Harbour / Common Seals (shown above on the left) have more finely spotted coats, and Grey Seals tend to be larger and have a longer muzzle, strikingly so in the males.

Harbour / Common Seals have their pups earlier in the summer, and they are much less conspicuous because unlike the Grey Seals, the Harbour Seal pups are generally born having already shed their lanugo and ready to swim around close to mum straight away. In contrast, the life of a Grey Seal pup begins with three weeks or more lying around on the beach, doing not much other than gaining weight and moulting into their proper seaworthy fur.  

Almost all Grey Seal pups are born here between mid-September and the end of November, and since this is outside Rathlin’s main visitor season, this special time is observed by very few people. And that’s certainly the way the Grey Seals like it, as they choose the most secluded, inaccessible shores of the island in order to pop out their pups in peace.

Seals must not be approached or disturbed at any time of year (and in fact intentionally disturbing them is an offence that attracts a hefty fine), but luckily on Rathlin it is possible to observe plenty of the pup action by looking down from the cliffs above, while the seals remain perfectly oblivious to any onlookers. Rathlin’s stunning clifftop walking trails offer multiple vantage points to view pupping beaches, and while you won’t get close views, a pair of binoculars or a camera with a big zoom lens is enough to enjoy their natural behaviour and the unbelievable laziness cuteness of these furry little bundles of joy.

There doesn’t seem to be much information readily available about the Grey Seal population on Rathlin (but see http://rathlincommunity.org/visit#seals). What we could find about previous seal surveys on Rathlin and elsewhere in NI centred more around Harbour Seals. Surveys had been conducted in August, as this is the main moult period for the Harbour Seals and the time when they can be expected to congregate in their largest numbers on the shores. Any Grey Seals present were counted at the same time, but numbers recorded poorly represented what was likely to be true maximum number of Grey Seals using the site. The August 2018 survey recorded 46 Grey Seals on Rathlin, which can be expected to underestimate the true total, but still marked Rathlin as one of the main hotspots for Grey Seals in NI, behind the largest concentrations at the Copeland Islands and Outer Ards, and on a par with numbers recorded at Carlingford Lough, Strangford Lough, and Murlough Bay.

Having noticed ourselves that year on year there seemed to be more Grey Seal pups appearing around the west end of the island, we were curious about exactly how many pups are born on the whole island each year, and whether the Grey Seal population is increasing. These are two questions we won’t be able to fully answer yet, but we set out to learn a bit more this year, and at least come up with a good minimum estimate of the number of pups born in 2022.

Each year we’ve seen the first pup appear in mid-September, always in the cave beneath the West Light – of course, at this time of year the beaches around the West Light are far better observed on a daily basis than anywhere else on the island, but still, we’ve never seen one appear elsewhere ahead of here!  Throughout the spring and early summer the Grey Seals are rarely seen on these beaches, but from August onwards they start to gather in numbers and lounge around on the rocks. The final week or so of the visitor season at the Rathlin West Light Seabird Centre provides a good opportunity to watch out for the first pup – the viewing platform at the top of the lighthouse gives a rather awkward but clear view down to the entrance to the cave.

The appearance of the first pup has been creeping earlier and earlier over the last few years – it was the September 14th this year (see Rebecca’s tweet above), the 15th in 2020, and around the 18th/19th in 2019.

It’s easy to spot a newborn pup – their bright golden yellow colour stands out against the black basalt rocks on Rathlin’s beaches. They’re also skinny and rather uncoordinated, looking and behaving like they are dressed in a baggy sleeping bag. Also it’s often possible to see what’s left of the umbilical cord still attached (and just once we’ve seen one so recently born that gulls were fighting over the afterbirth!). On a diet of incredibly rich seal milk, a newborn pup very quickly gains weight, and within a few days you can tell they have really piled on the pounds, as would you if you lay on a beach all day drinking gallons of milk so rich it’s basically like liquid clotted cream. Check out the difference between the pups in the video below – the older one is so rotund it literally rolls around on the rocks.

Once a pup gets to the two-week “no neck” stage, that’s when they start to moult their white lanugo, and it takes another 1–2 weeks to complete their transformation into a proper Grey Seal.

Before they graduate from the beach, pups go through a scruffy stage while they shed their fluffy white natal fur. In early December this year, once the pups had all left, we found patches of the beach still covered with the remains of this soft warm fur.

Also once a pup reaches about two weeks old, we’ve found that’s when to expect to see a big male hanging around – they will be waiting to get their chance with the female while she is still tied to feeding her pup on the beach. These huge, hulking bulls are far larger than the females, and the new mums are understandably protective of their pups and often not receptive to the male’s attentions (see clip below).

And it’s not just the male-female interactions that can lead to dramatic scenes viewed from the cliffs. While it’s fair to say Grey Seal pups are generally not the most dynamic animals to watch, sometimes a bit of patience in a pup-watching session is rewarded with endearing antics, heartwarming mother-pup interactions, or even the occasional big adventure – our favourite is this epic escapade from October this year:

This autumn, we tried to keep track of all the pups we could see as the season progressed. Some other fieldwork presented the opportunity to visit cliffs in parts of the island that we aren’t usually able to access, so we surveyed as many of the beaches as possible. We managed to visit most of the likely pupping places at least twice during the season, and the majority more frequently than that (about every 12 weeks). At each site, we counted any new pups that had arrived since the last visit to our total, and ignored any that appeared old enough to have been present previously. We ignored some pups that appeared at new sites having completed or nearly completed their moult, as we suspected these pups were mobile enough to have swum around from another nearby beach where they had probably already been counted.  

We were amazed at how quickly the pups added up! Most beaches with pups only had one or two at a time, but on the busiest three beaches we recorded up to 7-9 pups at once, and 10 or 11 pups over the course of the season. We also saw 3 dead pups over the whole season, which we have included in our count – these were all young pups (less than a week old) that we didn’t see alive. This seems a low level of pup mortality across all beaches for this year, as we’ve certainly observed a few more dead than that in earlier years, despite making less effort to check the pupping beaches.

The peak period for pups seemed to be mid-October, and by the end of that month we had recorded 91 pups. Then by 9th November we had reached 102 pups, and it was clear that the rate of new pups appearing was slowing down. But still they kept on coming!

Lucky last: the 108th pup to be counted in 2022, seen on 19th November.

Our latest pup this year was seen at only a few days old on 19th November, when most beaches were looking empty of seals of any age. Last year we saw a pup that was moulting in mid-December, and also a fully moulted pup resting on a beach on January 24th, although the latter may have already been independent for some time. But assuming no further pups pop up now, our final total count for 2022 is 108 pups [EDIT: there’s an update here].

The true number of pups born on Rathlin this year will be higher than 108, because no doubt there were pups on hidden beaches or in caves that we weren’t able to observe. We’ve no idea how many of these uncounted pups there might be – we guess it could be anywhere from a few to a few dozen – but we’re reasonably confident we have counted the majority.

This tells us a bit more about Rathlin’s Grey Seal population overall in the last few months – at least 108 pups born here this year means at least 108 adult females came to give birth on the island’s shores, while also attracting some (presumably smaller) number of adult males to sire the next generation. Somewhere there must also be some younger or subordinate males and non-breeding females, but over the season we have observed few Grey Seals not obviously involved in pup production. And now pupping is over, we’ve noticed there seem to be very few seals around at all, which makes us wonder where they might have gone. As always, the more we learn, the more we realise we don’t know!

And finally, another highlight of this year’s pup-watching was seeing something we’ve never seen before – a very striking and beautiful all-black pup! We don’t know of any pups of this melanistic colour form being observed on Rathlin before, so this distinctive young seal is definitely one to watch out for again in the future.

Wagatha Christie – investigating Rathlin’s mystery wagtail

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In August 2022, a rare and mysterious avian visitor spent nearly three weeks lurking in a horse paddock near Church Bay. But despite our best detective work, it proved tricky to get to the bottom of exactly what it was… this was a job for Wagatha Christie!

We recognised it right away as a male Yellow Wagtail Motacilla flava, a species that is rarely seen on Rathlin, and that is nowadays quite a rarity anywhere in Northern Ireland. But Yellow Wagtail is one of the most complex of bird species, comprising 15 or so taxa (most of which are considered to be subspecies, although some may be separate species) which are distributed all the way from Western Europe to Far East Asia. A couple of these subspecies occur quite regularly in Ireland and the UK, others are very rare, and many of them hybridise with each other to produce confusing birds that don’t quite match any of the illustrations in the field guides. Our bird turned out to be one of the awkward ones, and trying to figure out just what it was, and where it might have come from, was going to give the little grey cells plenty of exercise.

Living and birding on Rathlin now since 2017, we are rather out of practice with Yellow Wagtails. But for any that show up in this part of the world, the initial prime suspects are going to be ‘British Yellow Wagtail’ M.f.flavissima, which breeds in Britain, and ‘Blue-headed Wagtail’ M.f.flava, which breeds across a wide area of mainland Europe. However, the Rathlin bird did not immediately look like either of these forms. Its plumage was quite worn and scruffy, but the most striking features in terms of its identification were a big, clean white throat, and a predominantly dark grey head. These features alone suggested we might be looking at one of the subspecies from southern Europe. After an initial quick scan of some online images, ‘Ashy-headed Wagtail’ M.f.cinereocapilla, the subspecies from Italy, looked like a good match.

Various Yellow Wagtail subspecies, with the Rathlin wagtail for comparison. At first glance, the subspecies cinereocapilla (Ashy-headed Wagtail) looks perhaps the closest match. Image adapted from an article on wagtail evolution by Per Alström and Rebecca Harris, available at https://bou.org.uk/blog-alstroem-harris-wagtail-evolution/

Ashy-headed Wagtail is a very rare bird in Northern Ireland, so more reading was needed to see if our wagtail really could be this type, and we also put photos online for anyone more familiar with the various Yellow Wagtail subspecies to comment on. It quickly became apparent that the Rathlin wagtail had a bit too much going on in the eyebrow department (especially the bit in front of the eye) for Ashy-headed. Instead, it was a better match for ‘Iberian Wagtail’ M.f.iberiae, which doesn’t always have such a big eyebrow as shown in fieldguides or the illustrations in the image above. This generated increased interest among mainland birders, as there are no accepted records of Iberian Wagtail anywhere in Ireland. Perhaps this might be the very first one. Over the coming weeks, at least 16 people came to Rathlin to see the bird – a big twitch, by Rathlin standards!

To confuse matters, Iberian Wagtail commonly intergrades with Ashy-headed Wagtail, producing intermediate hybrids. Some authorities even lump all these (Iberian, Ashy-headed and their intergrades) together as one taxon, called ‘White-throated Wagtail’ (or sometimes ‘Southern Wagtail’), and consider them as a single separate species. Muddying the already dirty waters even further, all of these forms can also hybridise with Blue-headed Wagtail M.f.flava, which itself sometimes hybridises with Grey-headed Wagtail M.f.thunbergi, producing offspring that can apparently look very much like the ‘White-throated Wagtails’!

Our bird seemed to fit either a poorly marked Iberian Wagtail or at least something from the ‘White-throated Wagtail’ group, but clinching this was going to be difficult with so many potentially similar hybrid options. A crucial piece of the puzzle that we needed was a clear recording of the bird’s call. A 2016 Dutch Birding paper by Bot, Groenendijk and van Oosten contains sonograms of calls from numerous Yellow Wagtail subspecies and describes the differences between them. If we could produce a sonogram of a call from the Rathlin bird, we could compare it to the examples in that article and others available online, and potentially get a confident identification.

However, getting the call on tape was challenging, as our bird was stubbornly taciturn. We had heard it call a couple of times when we first found it, but since then it had been resolutely silent, especially at the times we stood nearby with phone in hand, finger hovering over the sound record button, hoping for it to make a noise.

On 13th August, Anthony McGeehan visited, bringing with him some good quality sound recording equipment. But luck didn’t seem to be on our side. The bird stayed right in the middle of its field refusing to make a sound, and there was a constant barrage of background noise – endless groups of chattering visitors walking past, loud vehicles rumbling by, people stopping to ask what we were looking at, planes overhead, even a hen party at the adjacent hostel chose this time to have an outdoor sing-song. Undeterred, we strategically positioned the microphone in the field and sat nearby to wait. Incredibly, almost as soon as we sat down, the wind dropped, everyone fell silent, and a blissful hush settled as all the vehicles, ramblers and rowdy parties went out of earshot, and the bird, as if realising that this was its cue, flew directly over the recorder and called several times. Result!

The main distinction between the calls of different Yellow Wagtail subspecies is how ‘rasping’ they are. Some forms, including Iberian Wagtail and Ashy-headed Wagtails have raspy calls, while others have ‘smooth’ calls. The calls that we’d heard from the Rathlin wagtail so far hadn’t exactly sounded raspy, but the differences are shown more clearly in the sonograms. The Dutch Birding paper showed that the raspy calls looked very different, with a very jagged shape compared with the smooth calls, and now that we had a good recording we should be able to see exactly what our call looked like.

Anthony’s recording of the bird’s call can be seen on xeno-canto, along with its sonogram (at the start, a gentle snort from one of the horses helps to set the scene):

And the verdict… a seemingly perfect match for Blue-headed Wagtail M.f.flava!

Yes, the sonogram has the smooth inverted V shape of flava (and also flavissima, thunbergi and beema, which appear to have more or less identical calls), and shows none of the jagged teeth shown by the iberiae and cinereocapilla sonograms. So does that rule out the ‘White-throated Wagtail’ group after all? Possibly not. Several articles suggest that members of this group, particularly iberiae, do sometimes make a smooth flava-like call, as well as their typical rasping call. A trawl through the recordings available on xeno-canto confirms that this is the case, with numerous examples of apparent iberiae, actually recorded in Iberia, that sound like the Rathlin bird.

After all that, we’re not really any closer to clinching an identification. Had it given a nice raspy call that matched the classic ‘White-throated Wagtail’ call, then it may have been considered acceptable as such. It remains possible that it was indeed a ‘White-throated Wagtail’, but the fact that its calls were indistinguishable from Blue-headed Wagtail casts a lot of doubt over this identification. Furthermore, looking very closely at the sonograms, the Rathlin bird‘s calls are possibly too smooth for even the smoothest, least rasping of iberiae calls, although the differences are extremely subtle. Based on that, while we wouldn’t completely rule out White-throated Wagtail, some sort of intergrade is probably now the prime suspect. Perhaps one parent was a White-throated Wagtail of some kind, and the other parent Blue-headed or one of the other smooth-sounding subspecies. Or could it be the hybrid between flava and thunbergi, sometimes reputed to superficially resemble Iberian Wagtail? We don’t know, and probably never will.

We’re not too disappointed though. After all, this was the first Yellow Wagtail we’d seen on Rathlin since 2017, and provided a very rare opportunity for us to see and study one of these birds on our patch. And this delve into the complexities of Yellow Wagtail plumages and calls will at least mean that, next time one shows up on Rathlin, we should at least have a better idea of what we’re looking at. Although we might have to wait another five years for the next one to come along!

Rathlin wildlife highlights for every season

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With autumn now gathering pace as summer fades into a distant memory, we’ve been looking forward to what’s ahead for the next few months and thinking of some of the many things we love about winter on Rathlin…

This autumn-winter highlights calendar is a companion to one we produced for the spring-summer season, and we’ve put both onto our new page about the seasonal nature highlights of Rathlin – you can find this here.

Striped Hawkmoth and TWO butterflies new to Rathlin in 2022

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When we completed our report on the moths and butterflies of Rathlin (you can find this here), we knew that before long we’d need to update it with further new species observed on the island, but we didn’t expect it to be out of date in only a matter of days!

We’ll produce a full update for 2022 at the end of the year, but in the meantime we have some noteworthy new additions to cover now, before we accumulate any more!

A mega migrant!

Perhaps the biggest discovery was a migrant we had been half expecting to find its way to our shores – we’d seen countless reports of Striped Hawkmoths from moth-ers the length and breadth of GB, and even one or two filtering across to NI. But after a few fruitless nights searching flowers after dark during the peak of the reports, we rather gave up hope of this year’s exciting influx reaching us. But then on 30th June we received a tantalising video clip from Rebecca Tanner that showed a mysterious hawkmoth feeding on Red Valerian flowers in the harbour, the very same place where we had tried our luck in previous weeks. In the shadowy footage, a large moth was bombing around at such speed it was mostly just a blur, but it was clearly something out of the ordinary. It started to dawn on us that we were about to experience some major moth-envy, and as we found a few frames that revealed the detail of the wing and thorax pattern, we realised we were definitely looking at a STRIPED HAWKMOTH on Rathlin!

We checked with Rebecca when she had obtained this footage – at 3am earlier that day, and in fact only minutes after parting ways with Ric while both were returning from a night survey for Manx Shearwaters. This of course only further enhanced our sense of grippage, but we applauded Rebecca for remaining alert at that hour, as all good moth-ers should be! This beauty had been merrily feeding only a few hundred metres away from us less than 15 hours ago… could there be a chance it was still around? We waited impatiently for nightfall, then tooled up with the butterfly net and torch and headed back to the Red Valerian to see if we could get a look at it ourselves.

As we reached the flowers, straight away we saw something big and fast-flying hovering about – that had to be it! One deft swipe of the net and it was in the bag. Too easy! Afraid of fumbling such a precious catch out of the net, we scurried back home to check it indoors. Remarkably it stayed settled and permitted us to grab a few photos for the record, then we took it back to the Red Valerian where again it very obligingly posed for a quick snap in situ. A moment later it revved up and took off north, spiralling high up into the night sky. We imagined it leaving the island and powering across the North Channel… where might be the next stop in its adventures?

A new butterfly!

Until this year, the Rathlin butterfly list has stood solidly at 17 species, unchanged for decades. Despite all our recording efforts during 2017-2020, we never managed to find any new butterflies, and although there are definitely a few species with the potential to pop up here, again we found ourselves almost giving up hope of that ever happening. So it was a very unexpected thrill to be bumbling about on a sunny Sunday in early May, and find ourselves tripping over a real stunner of a new addition. As it flushed from the ground and flew a short distance, it initially gave the impression of a grey-brown moth, but the flash of shimmering green when it landed with closed upright wings was instantly unmistakable – a GREEN HAIRSTREAK! This gorgeous creature then proceeded to feed at Celandine and Primrose flowers on the sunny bank, casually flaunting itself right in front of us, until we eventually had to tear ourselves away from marvelling at its beauty.  

Interestingly, Green Hairstreak is one of the species that Ian Rippey, NI butterfly recorder and oracle of local Lepidoptera occurrences, had predicted might occur on Rathlin. It is scarce on the north coast, but Ian told us there was one record at Fair Head in 2021 – not too far away as the hairstreak flies – as well as a population at Ballypatrick Forest a few more flaps beyond.

But even so we were amazed to be watching one here on Rathlin – how and when had it arrived? Surely we couldn’t have overlooked a small colony of Green Hairstreaks hiding on Rathlin all this time? Had they arrived last year and established themselves while we were away from the island? In pristine condition, it didn’t appear to have had a long or difficult journey to get to us. The calm weather preceding its arrival had perhaps been favourable for butterflies to make a sea crossing, but Green Hairstreaks are scarce on mainland NI. There are good colonies on Islay, but we hadn’t had much north in the wind direction to assist its travel across from there. Interestingly, the spot where we saw it happens to be almost exactly the same spot where we found the Vagrant Emperor last October, which possibly points towards it having followed a similar path as other migrants arriving on the island.

Anyway since that wonderful first encounter we’ve had no further Green Hairstreak sightings, so it remains a puzzle!

STOP PRESS!!! We’ve only gone and found ANOTHER new butterfly!

We initially thought we were having quite a rubbish year for butterfly sightings on Rathlin – after such a warm and sunny early spring, butterfly numbers have seemed noticeably lower than we’re used to during what’s been a relatively cool and damp summer so far. But despite the lack of general butterfly action, somehow we managed to record yet another new butterfly species – quite an incredible feat here!

This was another chance discovery, made on 22nd July. Lepidoptera records were piling up unentered and drafts of blog posts languished unfinished, but the sun was shining, so it was impossible to resist going out in the middle of the day to see what was on the wing. Barely 100m from home, two strangely small dark butterflies caught the eye, and as they fluttered up and down a strip of grass refusing to stop, I started to hallucinate that they might be something more interesting than just a couple of runty Ringlets. Ric wearily agreed to come to my aid with the butterfly net so we could put my wild ideas to rest. These two were red herrings – undoubtedly they were just runty Ringlets – but it was the few minutes spent watching them that meant we were both in the right place at the right time when the real star appeared. Again a small butterfly, but this time light blue, repeatedly flying around the top of the Ivy-covered hedgerow. This set the alarm bells ringing instantly – it would be odd behaviour for the Common Blue (Rathlin’s usual blue butterfly), but very characteristic of the Holly Blue. Unfortunately, like the Ringlets, energised by the warm sunshine, this butterfly was also not for stopping. We watched it dancing back and forth, over and around the foliage, willing it to pause for a moment. Finally it did, just long enough to snatch a view through binoculars of its pale blue underside with small black dots. But sadly not long enough for a photo, so you’ll just have to take our word for it!

Holly Blue is another butterfly species that is scarce on the north coast, although it is perhaps now increasing. Once again Ian Rippey had the facts at his fingertips, telling us of single records across the water in Ballycastle in 2020 and 2021, and also sightings in Cushendall in 2021 and Portstewart in 2019. Any Holly Blues that do find their way to Rathlin will find a distinct lack of Holly, but luckily we can offer plenty of Ivy instead.

We’ve made numerous attempts to watch for the Holly Blue appearing again at the same site, and this almost paid off on 26th July, when three glimpses of a pale blue butterfly suggested it was indeed still present. But frustratingly this evasive creature has not yet revealed any more of itself to us since, although we’ll certainly be continuing to keep an eye out for it.

The Holly Blue was here, honest! Seen on two dates (probably) but sadly no pics

More Rathlin Lepidoptera news to follow soon!

Our new report: Moths & Butterflies of Rathlin Island

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* * * * * UPDATE: in 2022 a further 30 species were added to the Rathlin list * * * * *

As you may already know, we’ve written an annual bird report for Rathlin each year between 2017 and 2020 (you can find all these here). But for 2021 we were away from the island for most of the year, so here’s what we’ve produced instead:

View the report here (19MB)

We’ve greatly enjoyed finding and recording Lepidoptera on Rathlin since 2017 (we’ve previously described our annual highlights for 2019, 2018, and 2017), and our obsession really hit a peak in 2020 when we were able to do more recording than ever before. Having accumulated a great deal of information, we thought we owed it to the moths to do something useful with it. So this report covers just about everything you wanted to know (and possibly also quite a lot of stuff that you didn’t!) about the moths and butterflies we’ve recorded on Rathlin.

In four and a bit years, we’ve added almost 200 Lepidoptera species that hadn’t previously been recorded on Rathlin before, including one that was the first record for the island of Ireland, and another that was a first for NI. We’ve also highlighted the numerous notable species that occur on Rathlin, and included details on all the macro-moth, micro-moth, and butterfly species that have ever been recorded here (as far as we’re aware).

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And if you’re looking for more of this kind of thing, you might like to check out our other Rathlin wildlife information resources on our Species Galleries and Resources page.

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Support Rathlin Stickybeak

We’re dedicated to making high quality resources that showcase and document Rathlin’s natural history, and we’re keen that these are freely available to anyone who is interested in the island and its wildlife. If our work has been useful to you, please consider supporting us with a donation. This is easy to do at our ‘Buy me a coffee‘ page. We’ve lots of ideas for future Rathlin wildlife projects and this will help make them happen.

A surprisingly successful wild goose chase

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Greenland White-fronted Geese on their way to the mainland on 11th April 2020, seen from Kinramer.

For five years now, we’ve been highly intrigued (and possibly slightly obsessed!) by Rathlin’s small wintering flock of Greenland White-fronted Geese and their mysterious daily movements. We had worked out that they roost on Rathlin at night and travel to somewhere on the mainland each morning, but we’d always wondered exactly where they spent their days. On 24th January 2022 we had the opportunity to literally go on a wild goose chase and look for them on the mainland. But before we tell that story, let’s have a goosey goosey gander at the background to this tale.

The Greenland White-fronted Goose Anser albifrons flavirostris is an endangered subspecies of Greater White-fronted Goose. The entire global population, estimated to be around 20,000 birds, breeds in western Greenland and migrates to Ireland and Britain for winter. By far the largest wintering populations are in County Wexford and on Islay, with smaller populations scattered mainly around Ireland and Scotland.

The most distinctive features of Greenland White-fronted Geese are their bold black belly stripes and eponymous white foreheads. Compared with the familiar Greylag Goose (rear bird in image on right) they are slightly smaller and darker with a smaller bill. They are also much shyer and less noisy than the Greylags. While Rathlin’s Greylag Geese are more or less feral, and are present all year round, the Greenland White-fronts are very much wild and migrate to their nesting grounds in Greenland each year, more than 2,500km each way.

Before 2017, Rathlin wasn’t known to be a wintering site for these birds, and there was little known about them in the local area (but check out this comprehensive annual report for details of their numbers at known wintering sites). Since we first noticed them in 2017, the Rathlin flock has only numbered up to 20 birds, so it’s not surprising that they had gone under the radar until then, especially with their stealthy habits. We have summarised our observations of the geese (and all other birds) on Rathlin each year in our annual Rathlin Bird Reports.

Part of Rathlin’s Greenland White-fronted Goose flock in late 2021. At this time, the flock of 19 geese included eight young birds, easily recognisable here by their lack of black belly stripes. By mid-January 2022, the flock had increased to 20.

Almost every time we’ve seen Rathlin’s Greenland White-fronted Geese they have been in flight, making their way across to the mainland in the early morning. A few times we’ve also seen or heard them returning again just on nightfall. There have been very few reports of the species anywhere on the nearby mainland, and it remained a mystery where exactly they went to each day. Just to get to the mainland these birds were flying at least 9km each way, a round trip of 18km at a minimum, so we were curious what might lead them to make that extraordinary effort on a daily basis.

During our first winter on Rathlin, we started to observe the regular pattern of behaviour in the White-fronted Geese, and we received interesting information from Richard Donaghey that in the past the species had been observed to feed in the Stranocum/Dervock area, although there had been no recent sightings.

On 15th January 2022, we happened to be at Kebble when we saw the flock of 20 Greenland White-fronted Geese leaving the island on their morning commute. From this location we had a clear view of their crossing to the mainland, and we watched closely as they crossed Rathlin Sound and reached the north coast somewhere close to Carrick-a-Rede, continuing inland until they went out of sight over a ridge. We checked a map to match the visible landmarks we’d seen them pass on their journey, and marked out an area that we guessed their destination would be within.

We couldn’t know for sure how far they might keep going inland, so we plumped for an arbitrary boundary of about 20km to start with, putting them somewhere between the north coast and the Dark Hedges. Interestingly, a very quick google of goose foraging distances turned up a 2016 Scottish Natural Heritage guidance report containing a handy table of core range distances for a selection of wintering species. We haven’t gone digging for where this data came from, but with 5-8km quoted for Greenland White-fronts, the Rathlin birds easily exceed that range just getting across to the mainland each day.

Then on 24th January we had to spend the day on the mainland ourselves, and we realised we finally had a chance to try following our favourite geese! We took the first ferry sailing of the day and hustled over to the Portaneevy viewpoint, where we watched across Rathlin Sound and scanned for the arrival of our geese. Visibility was a bit murky, and with no shelter from a brisk southerly the wind chill was absolutely baltic. We were the only fools out on the cliffs at that time, and we crossed our numb fingers that the geese would hurry up and get over here. Thankfully they didn’t make us suffer for too long!

Although we’ve seen the GWFGs heading for the mainland dozens of times, it was a new thrill to be there to see them arrive. We spotted them in the distance at 9.15am, rapidly approaching in neat formation, 20 of them all present and correct. Within five minutes they had crossed the coast about 1.5km to the east of us, and we watched them continuing inland until they disappeared from view at 9.24am. The chase was on!

We had zero experience of the local area and very little idea where we were going. But we jumped into our in our mobile bird hide car and set off anyway, heading vaguely goose-wards. As we trundled along the quiet rural lanes, we realised there were hundreds of suitable looking fields where a small flock of geese might hide out. Surely we were looking for a needle in a haystack here, but we pushed on deeper into the potential goose zone.

More by luck than any navigational skill, we took a left turn and found a convenient place to pull off the road and reassess our plan. By now it was 9.45am, and the landscape rolled out before us, a patchwork of green fields and rushy hollows. Suddenly a scattering of small brown dots in a field in the middle distance came into focus…no way, it couldn’t be… yep, definitely 20 brown dots with white foreheads…it was them!

Can you see them?
It helps to zoom in…
Gotcha!

Somehow we had stumbled on the Greenland White-fronted Geese at virtually the first place we had stopped. This was too easy – after five years of wondering where they disappeared to each day, we’d finally found the Ansers!

At least this was one more piece of the puzzle we’d found anyway. Presumably the geese would be pretty mobile around this area, and we don’t know if this would be a regular daytime site for them. We watched them for about 10 minutes. They looked pretty settled, some were grazing and others just resting. We had another appointment to get to, so we left them to it.

Locations of the probable roost and known daytime location of the White-fronted Geese on 24th Jan – 13km apart in a straight line, but as the goose actually flies it’s slightly more than a 26km return trip.

Once our mainland jobs were done, we had time in the afternoon to check in on the geese again before getting the ferry back to Rathlin. When we rocked up for another look about 3pm, they were still there, having moved less than 200m from their original location.

Back on Rathlin, as we got off the ferry we wondered if we could round off the day by seeing the Greenland White-fronted Geese return to their roost. So in the fading light we hurried up to Kinramer North to watch for them.

But this is where our goose-divining luck ran out for the day. Dusk turned to dark with no sight or sound of the Greenland White-fronted Geese. A Long-eared Owl came bombing past, silhouetted against the sky, giving a strange little squeak of surprise at finding two humans on its hunting patch. We heard more wingbeats extremely close, perhaps a Woodcock swerving round us. But somehow, we missed the geese arriving home. We don’t know all their secrets just yet!

Rathlin Island Flora photo gallery

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Rathlin has a spectacular and colourful diversity of plantlife, and over the last few years we’ve spent many happy hours exploring and recording the plant species we’ve found, amassing a large collection of photos in the process. We’ve now created an online gallery of a selection of these photos, to showcase the island’s flora and provide a useful resource for anyone interested in the wild plants of Rathlin. To see it go to

Rathlin Island Flora on Flickr

We’ve arranged the photos into albums by plant family, although for some non-flowering plants such as conifers and ferns we have lumped several families together for convenience. We’ve also aimed to arrange the family albums, and species within families, in taxonomic order, so closely related and similar species are usually close together.

The gallery mainly features vascular plants, but in time we hope to expand it to included non-vascular plants (mosses and liverworts) as we become more familiar with them. So far, the only members of this group that we have included are the Sphagnum mosses (which we also wrote about here).

At the time of writing, the gallery contains images of nearly 300 species, but it is very much a work in progress: the number of species of vascular plant currently known to grow wild on the island is in excess of 430 (plus plenty more that have been recorded in the past but not seen recently). In particular, a lot of grasses, sedges and aquatic plants are not yet featured, but there are also a few other common wild flowers that we still don’t have a picture of. We’ll be aiming to fill as many of these gaps as possible during 2022.

Every photo has been taken by us, on Rathlin, since 2017. For most species, we have used photos that show an overall portrait of the plant, usually focusing on the flower. However, in a lot of cases we have included additional photos that show particular identifying features, or which show the plant within its habitat. We’ve mostly used common names (rather than scientific names) of plants, to make it more accessible to normal humans as well as plant nerds.

Botanical highlights on Rathlin include a splendid variety and abundance of orchids, Northern Ireland’s only population of Pyramidal Bugle (more detail about that here), numerous other regionally notable species such as Oysterplant (see here), and a few curious carnivorous plants (including Round-leaved Sundew and two species of butterwort), among many more interesting, beautiful and uncommon species.

The most complete list of plant species currently available for Rathlin is J. Margaret Dickson’s A Flora of Rathlin Island (2003), which draws together historic records from various sources, updated with Margaret’s notes from her own extensive botanical recording on the island. This has been of great help to us in learning about the island’s plants, and our copy is now covered in scribbled notes and annotations on every page! Sadly Margaret passed away in 2020, but we are aiming to build on her achievements and produce an updated Rathlin flora list, incorporating some new discoveries made since the original list was published.

In the meantime, we hope that our Rathlin Island Flora gallery acts as a useful companion to Margaret Dickson’s work, providing photos for most of the species listed. Unavoidably, plant taxonomy changes all the time, and the up-to-date families, sequence and names that we have used do not correspond exactly with those used in A Flora of Rathlin Island, but hopefully it is not too hard to locate any particular species.

We hope you’ll enjoy looking at the gallery, and if it inspires you to get out botanising on Rathlin, do let us know what you see!

Support Rathlin Stickybeak

We’re dedicated to making high quality resources that showcase and document Rathlin’s natural history, and we’re keen that these are freely available to anyone who is interested in the island and its wildlife. If our work has been useful to you, please consider supporting us with a donation. This is easy to do at our ‘Buy me a coffee‘ page. We’ve lots of ideas for future Rathlin wildlife projects and this will help make them happen.