Migration madness

I’ve been back on Islay for a month now – and it’s flown by! The most exciting thing about this autumn has been the chance to catch up with our GPS tagged white-fronts from last year, hopefully combined with downloading their valuable data gathered over their summer away.

Is it bad to have favourites? Tag 21

The initial joy at finding an old friend alive, well and back on Islay with the tag still attached quickly changes to an extremely nervous wait once the downloading kit is unpacked and pressed into action. Is the tag still working? Will it send me the data? Will it painfully cut out halfway through a download? When the numbers start whirring through on the computer screen and the magic words "all data imported J" flash up (yes, it really does give you a J!) there might have been a bit of a fist pump and a little jig; anyone who’s ever seen me dance will know that’s not a pretty sight - hopefully no one was watching..

Migration data! Spring-Autumn 2014

Different birds = different colours. Tag 21 is red, 22 is dark blue

The good news is that 6 birds willingly parted with their data, giving us a remarkable insight into their migration routes, Icelandic staging areas and remote West Greenland breeding areas – this location data from the tags really is the next best thing to actually being there.

West Greenland happenings

It’s revealed some trials and tribulations associated with migration – and strategies the birds use to overcome them. The return leg from Iceland to Islay this year seems to have been particularly arduous – almost entirely due to the weather. Tag “BLO 19” (before anyone says anything I know she needs a proper name..!) left her journey really late, only leaving Iceland on the 10^th of November. She got her timings horribly wrong though, as she quickly met a series of Gale Force South Easterlies once she was out over the North Atlantic. Rather than pressing on into such a strong headwind and wasting precious energy, she ditched and sat on the sea for at least 6-8 hours. She did this twice more over the next 2 days before she made it to South Uist on the evening of the 13^th. Here she over-nighted before heading on down to Islay in the morning. To put this 4-day marathon in perspective, Tag BLO 27 completed the same journey (just less than 1500km), three weeks earlier, in 16 hours. Clearly, though, this strategy worked for BLO 19 – maybe if she’d ploughed into the headwind for 3 days she wouldn’t have made it at all – definitely  better late than never!

BLO 19 back to Islay. Circles indicate lengthy stopovers at sea

Wind map of the 12/11/2014 - middle of BLO 19's Iceland - Islay leg

Other birds tried a different tactic: just go with the flow! Two of these windsurfers were tags BLO 21 and 22. They were both blown off course on amazingly different paths back to Islay, 21 was up way north of the Faroes at one stage (look at first picture - northernmost red line), whilst 22 was well to the North West of the Irish coast (south-westernmost blue line). Other Greenland white-fronts clearly experienced similarly tricky conditions; a bird from Loch Ken in Dumfries and Galloway was seen in Norway, for instance.

In terms of ditching at sea these 3 Tundra bean geese in the North sea have life sussed though: not just taking a rest from flying, but catching a lift at the same time!

http://pelagicbirder.blogspot.co.uk/2014/11/bouncing-beans.html

Summer days

Currently on a pretty wet and windy ferry crossing back to Islay for the winter and quietly hoping i’m not going to be that guy that gets sea sick.. Which seems as good a time as any to re-start the old goose blog; once again you can get all your exciting goose related facts and anecdotes all in one place!

But for those still reading (a pretty grand assumption, i know..), you’ll no doubt be pleased to hear I’m going to start by talking about ducks. Ducks are cool. Everybody likes ducks. And over the summer I was lucky enough to work on what has to be our most enigmatic and mysterious UK breeding duck – the common scoter.

Scoters are sea ducks, spending almost all their lives in shallow seas feeding on shellfish, only fleetingly visiting a few Scottish freshwater lochs in order to breed. Because of this marine lifestyle, most people only ever see them from a coastal vantage point as a series of small black and brown dots bobbing around in the waves, which, i have to admit, has never really excited me before. But when seen close up they are actually a pretty striking bird – well, the males are at least; jet black with a splash of bright yellow on the top of the bill, the females are the classic fairly dull brown of so many duck species.

Male common scoter

Don’t let the “common” part of the name fool you – scoters are in real trouble as a British breeding bird, likely having declined by well over 50% in the last 20 years to the current population of maybe 40 pairs. We also know virtually nothing about them – which is a bit of a problem when it comes to coming up with conservation measures to stop them going extinct as a breeding bird in this country.

So it was pretty lucky that us species research folk at the Wildfowl and Wetlands Trust got some funding to investigate their breeding ecology on a couple of West Highland lochs over the summer. We started by finding some nests; easier said than done when you only have 15 females between two lochs that are both about 12 km long – serious needles in haystacks time. With a lot of effort and fair bit of luck we managed to find 9, not bad considering only 20-30 have ever been found before. We could monitor these nests using cameras and temperature loggers placed in the bottom of the nest cup to see how many hatched successfully and if they failed why, were they predated and, if so, by what? Similarly, any ducklings that hatched were followed to the point that they either disappeared, or successfully fledged. All pretty basic stuff, but never done before.

Cosy looking nest

Early impressions suggest that when nests were located within good cover (nice tall and thick vegetation, like old-growth heather) hatching success was pretty good, although some birds nested on some small grassy islands with very little cover – and these did very poorly indeed, not surprising really!

Scoter ducklings are very sweet. They leave the nest after a day or so and trundle down to the loch after mum, often a trek of a few hundred metres over rough ground and through thick, snaggly vegetation. Once on the water though, they are completely at home, diving to feed on aquatic invertebrates almost immediately, bobbing back up like fluffy corks and quickly bunching up behind an ever alert mum. Sadly though, more than half of them died within the first week – thereafter survival is fairly constant, but fewer than one in five of those that hatched survived through to fledging.

Common scoter female with week-old ducklings

Trying to reduce duckling mortality might prove tricky, but we think we can quite easily improve the nesting habitat available on these lochs – hopefully this will mean more successful nests and we get more ducklings onto the water; if mortality rates remain the same then a few more ducklings should survive to fledging. 

Bum deal?

So I realised I haven’t really gone into any detail as to how I’m spending my days and why. Cue a couple of slightly more science-y posts. You’ve been warned. For this project we’re using the full spectrum of data collection techniques; from very simple and easily repeated sampling in the field, to brand new and genuinely cutting-edge tracking devices. The telemetry is pretty cool and sexy, and is already showing us facets of the white-front’s lives that would be simply impossible to see otherwise. But, you’re going to have to wait for next time to hear about that! For now I’m going to explain how and why I’ve spent a fair bit of time ageing the birds here on Islay, and why I spend a couple of days every fortnight looking solely at goose bums. Yes. I do.

Adult Greenland white-fronts enjoying the Islay sun - it's a surprise, but you have to make the most of it!

It’s a pretty legitimate question to ask why! It might be surprising, but a goose’s bum can tell us a great deal about a goose’s recent history, current environment and its future prospects; to the extent that in some species during spring, it is even possible to predict, with reasonable accuracy, how many goslings an individual will return with the following autumn! Fat is the reason it’s possible to infer so much from a bum – like many of us, geese store fat in their bums. For any long-distance migrant, fat is their most valuable commodity; their fuel for migration. The fatter you are before migration, the likelier you are to successfully complete the journey and be in better condition for breeding. For geese, a bum is like a fuel tank. And big really is bootylicious.

We can, therefore, estimate any given individual’s body condition simply by looking at its bum and giving it a rating, or scoring, against some pre-determined scale. And we have one of those – made earlier of course. It’s called the Abdominal Profile Index (API) and is the basis of a lot of what I’m up to. The beauty of the API is that (with an experienced eye for a goose bum!) it is extremely quick and easy to score the body condition of large numbers of individuals – and from a distance.

When your diet is almost entirely vegetarian, it can take a lot of work to put on weight. Eating high quality food, and/or being able to spend long periods of time feeding mean an individual can fatten fairly easily. However, it may be that there is variation in the ability of individuals, flocks or even populations to access sufficient food resources to put on weight – and, if so, we would expect to see variation between their API’s as a result. Have a quick look at white-fronts in the photos; you should be able to see a clear difference in the size and shape of their bums!

This variation is most visible and important during the autumn and late winter/early spring, when the geese are feeding up rapidly just after and just before migration – to recoup the fat lost on the way here and to put on those extra few pounds prior to leaving. At other times of the winter, being very fat isn’t necessarily a good thing – being heavy slows you down and makes you less manoeuvrable, in turn making you more vulnerable to predation. The geese respond by regulating their body mass during the middle of winter – storing fat, but not compromising their survival.

We are looking at API variation at three scales with the Islay white-fronts. The first is between populations. The API’s on Islay as a whole can be compared with the birds that winter at Wexford in Ireland – a population that is doing much better than any other. If Islay API’s are significantly lower than Wexford, especially at migration departure point, then that would suggest the Islay birds are being restricted by their wintering site. The second scale is between the different flocks (or sub-populations) here on Islay. This will help determine if some flocks are unable to access resources as well as others; which will tie in neatly with work we’re doing characterising the habitats the white-fronts prefer (and where it’s available) and recording disturbance levels through the winter – both  potential causes of body condition variation. The third scale is at an individual level. Having a number of neck-collared birds means we can follow and individual’s body condition through the winter and relate this precisely to the areas and habitats they’ve used through the winter.

a family group in Iceland. Spot the juveniles!

Who knew a goose bum could tell you so much?! Ageing, on the other hand, does pretty much exactly what it says on the tin. It is equally easy, simply counting the number of juveniles and adults in each flock and converting to a proportion or percentage. Luckily, it is quite easy to separate an adult white-front from a juvenile, with a few characteristic differences that can be easily seen in the field. The most striking is the lack of the black belly-bars on the juveniles. Equally, the juveniles (to start with at least) are missing the white “frons”, or forehead, seen on the adults. Finally, the juveniles have a dark nail, right on the tip of their beak. This starts fading to the pale orange-white of the adult fairly quickly though..

2 juveniles with a parent. One in the background too!

Again, proportion of young is informative at different scales. At its simplest, the proportions of juveniles from all the wintering flocks get collated to calculate the productivity of the global population annually. Clearly, this is very useful for monitoring the long-term population trends of the Greenland white-fronts – which make pretty grim reading; a 40% decline in fewer than 15 years. It is also possible to compare between wintering populations. This year (so the 2013 breeding season) the Islay birds seem to have done pretty well, sitting somewhere around 16 – 17% young. I haven’t seen a global total yet, but it seems that other winter resorts have fared pretty poorly again. Last year, for instance, global productivity was about 4%. To put that in perspective, that’s essentially one successful brood per hundred adults. Not particularly clever.  Even productivity of 17% is only five or six pairs returning with goslings. They can get away with that, being a long-lived bird with high annual adult survival rates – they can’t at 4%. And they’ve had poor breeding seasons for a number of years now. We can also look at productivity between flocks on Islay. Given long-term datasets, it may be possible to link some variables – habitat quality, for instance – to variation in productivity within the island.

Losing it

Let me clear one thing up before I start. I’m not talking about mental meltdowns here; I’m doing pretty well. If you’re thinking Adam Scott chasing a major title, or Neil Cavanagh during exam season, I’m afraid you’ll be disappointed. Instead, I’m focussing on losing yourself, or a part of you. Might sound pretty deep and philosophical – it’s not.

The reason for all this lost chat is that Islay seems to be filling up with waifs and strays. Unsurprisingly, geese feature quite strongly here – but two I have particularly enjoyed. The first is a juvenile pale-bellied brent goose, who has had to resort to hanging out with the barnacle geese. Pale-bellied brent breed about as far north as you could wish to go (probably further..), right up in high Arctic Canada. They migrate south via Iceland, where I would guess this youngster got separated from his parents and ended up with the masses of barnacle geese.  Similarly, my second refugee (a juvenile pink-footed goose) probably lost its family in Iceland too and hitched a migration-route lift down to Islay with the Greenland white-fronts. Both these babies have actually not done too badly; about 80 brent geese even winter here on Islay (though some distance from this juvenile) and, whilst pink-feet tend to winter in mainland Scotland down to Norfolk, this baby pinkie will probably return with the white-fronts to their Iceland mid-migration pit stop, where, with a bit of luck, it’ll find its own kind returning to breed. The baby pinkie I see almost every day, always with the same white-fronts. I’m developing a bit of a soft spot for him!

The juvenile pink-footed goose in with some young Greenland white-fronts. Daddy white-front looking very worried in the back!

It’s not that unusual for ducks and geese to end up on a different migration flyway (what we call a major migration route) by accident. This year on Islay there have been reports of a few lesser Canada geese – B. c. hutchinsii for all you bird nerds out there. In layman’s terms that means real ones, not just the big fat ones sitting on a golf course near you – and a green-winged teal; both North American species. Previous years have seen snow geese (N. America) and red-breasted geese (breed in Siberia, winter in S.E. Europe) turn up here.

Red-breasted goose. An endangered species that breeds in Siberia. 

It just goes to show what a challenge migration can be, especially your first one. It’s a key reason why young migratory geese remain with their parents for much of their first year; learning and inheriting routes, staging sites and winter destinations. Most birds don’t use this strategy, with adults often migrating some time before the juveniles are ready to go. These youngsters really are in at the deep end, having to follow a strong instinctive drive and learn routes and safe stopovers en route.

Iceland gull showing off its pure white wing-tips over a dark and stormy Loch Indaal

The next two wanderers to pitch up here were two of the northern gull species that arrived in the New Year, almost certainly due, to some extent, to the wild and windy weather. Glaucous and Iceland gulls are both most commonly associated with Iceland, and, to be fair, I think the Icelanders picked the prettiest one to bear their name. They’re both very similar, but the Iceland gull has a slightly rounder, friendlier, forehead, whilst the glaucous has a seemingly meaner, more aggressive facial expression. The most striking feature of both is their completely primary wing feathers. This has given them the moniker “white-wingers” amongst birders and is more noticeable than you think, even amongst a number of herring gulls – which can look pretty similar again, but have distinct black wingtips.

Glaucous gull. A mean looking bird!

Finally, I saw a common crane up here last week. Quite what that was doing up here is anyone’s guess; there aren’t any others anywhere nearby. Sadly, it was just flying over, so I never got a good look or a photo, but there are rumours that it was seen a week before my sighting, so hopefully it is still tucked away somewhere up here. It certainly was doing a much better job scaring the barnacle geese than a few scarecrows and gas guns. I don’t think they’d ever seen anything that big before, and obviously reckoned it could eat a load of them all in one go if it wanted to. It frightened the living daylights out of them!

And so to the losing a part of you part of the story. A bit of a mouthful.. Yesterday I saw the young stag I photographed early in the autumn (http://chasingeese.blogspot.co.uk/2013/10/early-impressions.html) down on the Mull of Oa. Clearly he’d been in the action and had a scrap or two during the rut because his antlers had taken a fair bit of wear and tear. His right one had snapped off just above the brow tine and the left brow tine was also looking somewhat abbreviated. At least he’ll be shedding them pretty soon and growing a new pair over the summer for next autumn.  He’s certainly pretty vain and enjoys posing for photos, walking up to about 15 yards from my office (the car) and then standing beautifully silhouetted against the rising sun. If only he had a full set of antlers…

Looking pretty scruffy..

Beauty and the beach

Mum and dad managed to get across the pretty wild sea over the weekend for a quick Islay safari and whilst taking them on a couple of game drives I realised that my life has got very goose orientated recently. So I thought it was time for a little bit of light, non-goose related, relief on here too.

Not a goose to be seen at Machir bay

And where better to start than with couple of Islay’s most imposing residents?  Think of Scotland and big, bulky red-heads might not be too far from the front of many people’s minds – but these two are of the animal variety! Highland cattle are really quite common here; they can withstand almost all the seriously variable weather can throw at them and thrive on the rougher hill ground that other stock struggles to cope with. Aesthetically they just seem to “fit” with the landscape here too. They stare at you from behind a ginger fringe with a seriously uninterested, yet not totally vacant, expression – as if they’re slightly puzzled by you, but can’t be bothered to work out why. But then, maybe that’s just reserved for people looking at geese with a telescope..

Just what are you doing?

 

In the winter the highland cattle are joined on the marginal hill fringe grazing by the red deer. By now the rut is over, and the boys can re-group in little bachelor herds, have a bit of a feed and suss out who got up to what over the last couple of months. It looks a little bit like a slightly hungover, post night-out debrief with the boys over a greasy fry-up. This guy, as well as having probably the most impressive set of antlers I’ve ever seen on a wild staggie, definitely seemed to be feeling the effects and was clearly needing to fill that belly before he felt ready to face the world again.

A weary look in his eye..

 

It’s not just the wildlife that’s spectacular here though; Islay has some pretty amazing beaches. At this time of year they are windswept, deserted and beautiful. Mum was pretty quick to get the camera out and the results will probably render the Islay tourist board redundant. Ok it’s not very warm, but who needs to jet out to the Caribbean?

Big strand beach

looking towards Laggan point

 

Totally addicted to... ring reading?!

First, the confession. I love looking at rings on birds. If that sounds pretty weird.. please bear with me – I’ll try to explain.

You may, or quite understandably may not, know that a lot of research on bird migrations and populations has involved putting a small, individually numbered metal ring on the bird’s leg. This has been done for years, by experienced, serious and (no doubt) highly intelligent researchers, but also by a significant number of amateur birders for whom it’s simply a hobby. Whilst this system has thrown up some mind-blowing data over the years, it inherently relies on a ringed bird somewhere down the line either being re-captured or being found dead (or shot in some species..) simply because the rings are small, pretty inconspicuous and almost impossible to read on a bird hopping about in the wild.

A bit of a game-changer is the use of individually coloured or coded rings. This allows known individuals to be re-sighted from afar, whilst free and alive; opening up a realm of research opportunities.

 

Coded Greenland white-fronted goose neck collars ready to be deployed

 
But you have to catch your chickens before you can count them. Sorry. With almost every type of bird comes a method of catching them. And whilst mist nets and clap traps sound exciting, there is only really one way to cook your goose, so to speak – to cannon-net it. It sounds spectacular, and it is. Anything using a lot of black powder, projectiles and 1000 volts is pretty much guaranteed to be.  It sounds easy, and it’s not. Which is a major reason why this blog post comes some time after the previous one – we’ve been trying to catch the Greenland white-fronts. And we struggled.

WARNING: The video clip makes it look easy, but then they (Prof Stuart Bearhop – my Masters supervisor at the University of Exeter – and the Irish Brent Goose Project) were catching brent geese. And there are lots of them. And they’re a little bit thick. More on them in a future post..

The beauty of catching geese is that we can individually mark them with leg rings and neck collars. By subsequently re-sighting and identifying these marked birds, they then can tell us all sorts of information about that individual, from life expectancy and survival rates, to migration routes,  to small everyday details, like which fields they like to feed in when – even which social network it belongs to!

 

Coloured and coded leg rings on light-bellied brent geese  in Iceland - the subject of a current study on social networks within flocks

 

Every white-front that gets caught receives a fair bit of jewellery, as well as being thoroughly weighed, measured, swabbed and sexed. First is a small metal ring which is issued by the British Trust for Ornithology (BTO) – every bird that gets ringed anywhere in the UK will have one of these – but then comes the bling. Each white-front then gets a white plastic leg ring and orange neck collar, engraved with an individual 3 digit alpha-numeric code. From now on, that goose can be recognized wherever it goes, and if the sightings are reported and collected we can slowly build a picture of what it gets up to.

 

Collared and ready for release - the story begins!

 

The re-sighting process can vary from being infuriatingly difficult to a walk in the park (literally in the case of Dublin brent geese). It is immensely rewarding though and strangely addictive. There are many levels of enjoyment, from the moment of triumph when you finally crack the last letter on the collar that had seemed half invisible and with a bewilderingly shape-shifting ability, to the joy of seeing old friends again (corny, but true). For me, though, it’s the stories that come from it that are amazing. Where and when was the bird caught? Where else has it been seen before? And of course each time that bird is re-sighted, the story grows. Has it paired up? Did it have young this year? All this data is invaluable to researchers, but it is also unbelievably satisfying and fascinating personally. It connects you to that animal in a very special way.

 

Not just geese! A colour ringed chough on Islay

 

So enough of all that emotional stuff. I would urge you though, if you see a ringed bird, or any marked animal, take the time to try and read its tag and just as importantly report it. The information is really valued. For birds, a good starting point is the BTO website (http://www.bto.org/). For any of you on, or due to visit, Islay there are any number of marked birds here. All the goose species found here have marked birds, as are many of the choughs. waders are also often worth a good look. If anyone sees any collared white-fronts.. I want to hear from you! Ed.Burrell@wwt.org.uk. I’ll try and fill you in with some details of the bird where possible. Just as a teaser.. there are white-fronts on Islay at the moment caught on the island, elsewhere in Scotland, in Ireland and even Greenland; keep an eye out.

So there is my defence for my addiction to ring reading. Try it, you might get hooked..

 

 

Caught as an adult (i.e. >2 years old) in Ireland in 2001, P3A hadn't been seen since 2007 until we met a couple of weeks ago on Islay. At least 14 years old and still going strong. A shoddy bit of photography on my part, but a good story.. It's what it's all about!

 

Sitting on the bog..

This week I seem to have spent a lot of time lying down on a bog in the dark trying to establish where my white-fronted geese are going to bed. And white-fronts like nothing more than a nice wet bog to sleep in. Maybe all the Sphagnum moss makes a comfy mattress? Watching their bedtime movements isn’t quite as creepy as it sounds. Nor, as it turns out, as easy. 

White-front roost habitat. With the Opera rocks behind

You might ask why bother? Firstly, it’s good to work out where the birds are roosting, simply because a safe roost site plays an important part in the bird’s survival throughout the winter. By knowing the location of roosts and having an idea of the numbers of birds using each site, we can ensure they are protected, remain undisturbed and appropriately managed. This has been done before, about 20 years ago – the problem is the white-front population here on Islay has changed dramatically in that time – and the early indications are that their roosting habits may well have changed too. Secondly (and potentially more interestingly), we might be able to get an idea of linkages between roost sites and feeding areas, i.e. individuals from one roost may feed in a certain area, whilst birds from another roost feed somewhere else.  Taken in conjunction with the work we’ll be doing catching, marking and GPS tagging some birds (more of which soon!), this would give us a clearer idea of if, as seems likely, the overall Islay population is made up of lots of smaller flocks; a meta-population, if we’re getting technical. If this is the case, and we see that some flocks are doing better or worse than others, we may get an indication as to what is causing the birds problems.

Which explains why I have been hiding in clumps of heather and ditches first thing in the morning and last thing at night. Which has meant some early starts. Which can be a struggle for me. And the white-fronts are pretty shy about letting you know where they sleep. Countless times I’ve seen them fifty or sixty suddenly appear out the dark and apparently drop into a pool – only to find absolutely no sign of them the following morning. I think a lot of the time they are just having a bit of a drink and wash before heading off somewhere else. It’s great being out and about though. Most memorable this week has been the sight and, best of all, the sound of hundreds of geese passing literally a few feet from me on their way to feed in the morning. They were battling into a headwind and so were almost touching the ground with their wingtips, trying to keep under the wind. They were just lifting enough to flick over the gorse bush that had a me in it – really a brilliant experience!

Approaching barnies

 

Staying on the flying geese theme, I’ve had some fun this week playing with the camera and flying barnacle geese. These funny little black and white lawnmowers look a bit more like a proper goose when they are airborne – and the sheer numbers of them are quite breath-taking sometimes. I did a quick count, and I reckon there are 340 in this photo. Which is framed pretty tightly. I think there were about 10,000 in view at this point!

340 (?!) barnacle geese

 

I did feel a bit sorry for them at times. Clearly, being a goose in a hail storm isn’t much fun. They stuck at it though; they’re hardy little things and that grass won’t eat itself. They looked like they enjoyed the old preen and wing stretch afterwards..

Wet barnies

 

Post shower stretch