Tuesday, 12 January 2016

Ten cool Northern Fulmar facts

In mid December I visited South Landing, at Flamborough Head. I was pleasantly surprised to find a pair of Fulmars displaying on a chalk cliff ledge, and, when I later mentioned this to a couple of local birdwatchers they replied, 'Yes, they are back', as if it was an expected event for them. This made me realise how little I knew about Fulmars. Back home I started reading about them. I also obtained a copy of 'The Fulmar' by James Fisher, which, aided by an injury that has left me temporarily house-bound, I've been reading and just finished today. This post is a compilation of facts on this fascinating bird.

1. The Fulmar is a superb glider of the open Northern ocean. They brave storms and rough weather when other sea birds might seek refuge in the coast. They use the wind to range over large distances, almost effortlessly. Their flight is quite different to gulls, with stiffer wings. Using the updrafts generated by cliffs, they often wheel tirelessly round and round their breeding sites in a characteristic aerial flight display.
2. The Fulmar is one of just three bird species recorded several times on or near the North Pole. The others being the Snow Bunting and the Black-Legged Kittiwake. In summer, they regularly patrol the Arctic pack ice in the Arctic Ocean pack in search of food. Watch this short clip of a Fulmar sighting near the North Pole.

3. The word fulmar appears first in written language in an Icelandic Saga written about 1200 AD. It has a Norse origin meaning 'foul gull', presumably referring to the oil that they spit out when alarmed and superficial resemblance to gulls. The inhabitants of St Kilda, who spoke Gaelic, also used the word fulmar, while the word was eventually lost in Iceland and replaced by the now used filingur. The fact that the same name was shared between Iceland and the Hebridean island is thought to originate from a time when commerce between Iceland and Scotland was well developed, possibly around the year 1000, in the time of the Vikings, who spoke Old Norse.
Fulmar pair displaying, South Landing 14/12/16.
4. Fulmars return every year to the same nest sites to meet their long-term parter, well ahead of the breeding season, often in December. They greet and bond with each other billing and head bobbing, with much loud cackling calls while keeping their bills open and throat distended. They visit their nest sites on the cliffs on calm days increasingly all through winter until the breeding season. Despite the long-term pair bonds, there is much 'visiting' of neighbours and extra-pair copulation both by males and the females. However, genetic studies show no extra-pair paternity. After mating, Fulmar return to sea before egg laying (the pre-laying 'exodus'), where they presumably store up on reserves for their long incubating period (up to six weeks). Unlike other birds, female fulmars store sperm and the last copulations might take place three weeks before egg laying. They lay a single egg in May, with no replacement if lost, on a bare cliff ledge, or a scrape or rabbit burrow on steep soil slopes. Both parents incubate for about of about six weeks, with changeovers every 4 days. Their superb gliding abilities allow them to range hundreds of miles from the nest site itself in search of food.

5. The oil spitting habit of the fulmar is the defence mechanism of the chick. Fulmar chicks are left on their own from about 2 weeks of age, when they no longer need brooding, while parents travel to get food.  The rapidly fattening chick can by this time defend itself by oil spitting, something that ornithologists trying to ring them have repeatedly experienced. The apparently badly smelling oil, which is a stomach secretion, matts feathers and can cause the death of attackers (large gulls, skuas, falcons) by preventing adequate thermoregulation. The fully grown young, weighing at that time more than its parents (chicks over 1 kg in weight are not rare), eventually fledge in late August or early September and both adults and fledglings move into the ocean. The cliffs become then devoid of fulmars for a couple of months, until their return in the winter.

6. Fulmars are long lived. Adult mortality is low. The longevity record is almost 44 years old, but they are likely to regularly live longer. They mature slowly and breed for the first time at 6-12 years old.  The young birds prospect potential nest sites, often ranging far from their natal sites, and may settle on the cliffs regularly for several years before actual breeding happens. Prospecting birds have been often seen hundreds of miles from the sea in inland crags and cliffs. There are some breeding colonies in quarries miles from the sea.
Northern Giant Petrel in South Georgia photographed by Liam Quinn, CC BY-SA 2.0 via Flickr.

7. The Northern Fulmar's closest relatives are the very similar Antarctic Fulmar and the Giant Petrels, awesome predators and scavengers from the Antarctic. There are two subspecies of the Northern Fulmar, Atlantic and Pacific which some recommend elevating to species status. More distant relatives are other 'tubenoses' like the Storm Petrels and Albatrosses.

8. There are a gradation of colour forms in the Fulmar. One of the extreme forms, the Blue fulmar, which is all slate grey, breeds in the High Arctic and is an occasional visitor of British coasts. The British and Icelandic Fulmar are of the light form, where the body, neck and head are pure white, and the wings and mantle grey.

9. In the last century the Fulmar has colonised large areas of the North Atlantic.  Before 1878, when it first bred in Shetland, the only other breeding colonies were in the small archipelago of St Kilda, off the outer Hebrides (where it has been known to breed at least since much earlier than 1697), Iceland and High Arctic islands. Since then, it has undergone a astonishingly swift range expansion, most likely from an original north Icelandic population, and in the twentieth century colonised most of the cliffs around the UK, Norway, Denmark, and Northern France. The first English Fulmars in recorded history bred in the RSPB Bempton Cliffs nature reserve in 1922.

10. Fulmar feed on small fish, squid, crabs, pelagic molluscs and krill that they hunt from the water surface or in shallow dives, but they are also scavengers. They are rapidly attracted and will feed in numbers on dead, beached or floating whales, and used to come to whales being processed by whaling ships. They will also follow trawlers and feed on offal and fish discards. They will also feed on migrant birds, presumably after then fall into the sea exhausted.  Their scavenging behaviour is most likely aided by their highly developed sense of smell. The fulmars use of whaling and trawling discards, a plentiful food resource was hypothesized by James Fisher to have spurred their range expansion - but recent diet analysis suggest that their reliance on these sources of food might be less than it was thought.

Bonus fact: The inhabitants of St Kilda relied to a large extent in fulmars. They used Fulmars, Gannets and other sea nesting birds for their feathers, eggs, skins, oil and meat. Even fulmar bones were used to fasten their jackets together. The young about to fledge were highly appreciated, and they were were collected the cliffs in mid August, just before they fledged, and when they were at their heaviest. The oil, which solidified when cold into a waxy substance, was collected from the young, poured into Gannet stomachs and stored in small stone buildings with turfed roofs called cletts. Whatever they couldn't use of the birds, they recycled, together with ashes and their own urine to fertilise their fields. Fowling wasn't restricted to St Kilda, it was a traditional way of life in Iceland, Greenland and the Faeroes, but it almost completely stopped when it was made illegal in the late 1930s after an outbreak of psittacosis that affected people processing the birds.

More information

Lockwood, W. B. (1954) Linguistic notes on Fulmar. British Birds 47, 336-339.

Fisher, James (1952) The Fulmar. Collins New Naturalist series, London. 496 pp.

Phillips, R. A. et al. (1999) Diet of the northern fulmar Fulmarus glacialis: reliance on commercial fisheries? Mar. Biol. 135, 159–170.

Kerr, K. C. R. & Dove, C. J. (2013) Delimiting shades of gray: phylogeography of the Northern Fulmar, Fulmarus glacialis. Ecol. Evol. 3, 1915–1930.

van Meurs, R. & Splettstoesser, J. F. (2003) Farthest north polar bear (Ursus maritimus). Arctic 56, 309.

Martin M. (1698) Voyage to St Kilda. London.

Hunter, F. M., Burke, T. & Watts, S. E. (1992) Frequent copulation as a method of paternity assurance in the northern fulmar. Anim. Behav. 44, 149–156.

Friday, 1 January 2016

The variable Redpoll

Redpolls are small finches with a tiny bill, a crimson spot on the forehead and a little black bib and mask giving them slanted-looking eyes. Their plumage is so dense that on their faces it can partially hide their bill, giving them a flat face. They are found from the Arctic (where they are resident), to subarctic and temperate open forest and scrub and specialise on small seeds, mainly from birch, but also alder, willow, spruce, larch (above) and pine cones. They will also feed on various wildflower seeds near the ground.
 Redpolls are very entertaining to watch as they feed, as they reach catkins and cones using acrobatic, agile movements, reminiscent of tits. In addition, they can use one foot to hold onto a stem, a bunch of seeds or catkin to reach the seeds more easily, like goldfinches. They can apparently store up to 2 g of seeds in a expandable pouch in their throat, to eat later in less exposed conditions. Redpolls have been seen 'bathing' and burrowing tunnels in the snow. These tunnels have unclear function, as they don't appear to use them to shelter from low temperatures, rather, they appear to fulfill a social role, or just be a form of play.
  Redpoll flocks have erratic, nomadic, movements in winter in search of seeds, often travelling in the company of Siskins. They also have 'irruption years', following failures on the seed crops on which they rely, or high population densities after a good crop year, often spurred by cold weather. One of the largest irruption years were in the winter of 1995-96, where Arctic and Common Redpolls arrived in the UK in good numbers.
 The taxonomy of Redpolls has been very fluid, with three species, Arctic, Common and Lesser -each with various described geographic subspecies- recognised, but at some point six were described. The browner, small and very streaked 'Lesser Redpoll' breeds in the UK. Diagnosis was based on the lightness and amount of streaking in the plumage and also bill shape and size and overall size. However identification is often difficult, as there is a lot of variation, and many individuals would fall in between the 'classic' species descriptions, resulting 'in much collective head-scratching' in the words of Riddington and colleagues.
  A recent study by Nicholas Mason and Scott Taylor from Cornell University, sampled 77 Redpolls from around their distribution range and looked at the diversity across their genomes, niche differentiation, morphological diversity and gene expression patterns. Surprisingly, all Redpolls were extremely similar genetically, with barely any genomic differentiation between 'species'. The different colour patterns and bill shape can be explained by different gene expression patterns (e.g in response to temperature), but the authors did not find a clear-cut morphological differentiation between species, as many individuals were intermediate. Although recent adaptation to particular local conditions, for example the dominant available seeds) might have happened, it is likely that the nomadic migratory movements of Redpolls result in a lot of dispersal and gene flow between populations and incipient regional varieties, preventing differentiation and subsequent speciation. Perhaps we should just enjoy Redpolls as a delightful bird on its own, and worry less about tidying individuals away into imaginary boxes.

More information
The Cornell Lab of Ornithology Cool Redpoll Facts.

Riddington, R., Votier, S. C., & Steele, J. (2000). The influx of redpolls into Western Europe, 1995/96. British Birds, 93: 59-67. Pdf here.

Gustave Axelson (2015) From Many, One: How Many Species Of Redpolls Are There? Commentary on Mason and Taylor paper on the The Cornell Lab of Ornithology blog.

Mason, N.A. and Taylor, S.A., 2015. Differentially expressed genes match bill morphology and plumage despite largely undifferentiated genomes in a Holarctic songbird. Molecular ecology, 24: 3009–3025. Here.

Collins, J. E., & Peterson, J. M. (2003). Snow burrowing by Common Redpolls (Carduelis flammea). The Kingbird, 53, 13-22. Here.

A male Redpoll feeding on Alder catkins
A Redpoll feeding on Rosebay Willowherb.

A male Redpoll on Alder
An individual on Alder, illustrating their ability to hang upside down from thin branches.