Just skimming the surface
The black skimmer is one of three skimmer species in their own family: the Rynchopidae. Skimmers are yet another fantastic example of the avian beak as a highly adapted tool. In this instance, the lower mandible extends much further than the upper. The skimmer flies low over water and drags the lower mandible along the surface before hooking up an unsuspecting fish. Of the skimmers, the black skimmer is unique in being the only bird with slitted pupils. The cat-like vertical slits are thought to minimise the amount of light reaching the eye from staring so constantly at the water's surface at close proximity.
The skimmers are one of the firm member families of the charadriiform suborder Lari. I say firm as ,whilst taxonomists can agree on the inclusion of five families, others, such as the coursers (Glareolidae) and Egyptian plover (Pluvianidae), have debated inclusion. The remaining families in this order will be represented over the coming days but for the skuas: large, brown sea birds known for their kleptoparasitic bullying of other birds.
Day 40: Lesser black-backed gull - Larus fuscus
One ring to rule them all
As gulls go, the lesser black-backed gull does not stand out ecologically or aethetically (all though I think the smartness of gulls is under-appreciated). Larus is a genus of large, white-headed gulls in the gull family Laridae (other gull genera tend to have dark heads). The reason that the lesser black-backed gull is so interesting is because of its evolutionary relationship with the familiar seaside herring gull (Larus argentatus)
To us in Britain these two gulls are easy to tell apart with the lesser black-backed gull being darker with the bright yellow legs and the herring gull being pale-backed and pink-legged (the latter has also probably stolen your lunch). However they are part of a ring complex of species. As one moves east over Europe to Siberia the lesser black-backed gulls grow slightly paler becoming the Heuglin's gull (Larus heuglini). Continue through to far-east Siberia and Heuglin's gull is replaced by the grey-backed, pink-legged Vega gull (Larus vegae). Cross into North America and, paler still, we have the American herring gull (Larus smithsonianus). Finally, across the Pond and back in Britain the European herring gull is the dominant Larus species.
Thus, when moving east, the differences between populations are slight and all species can hybridise with neighbours but by the time the circuit is complete the sympatric herring and lesser black-backed gulls are so different as to be obviously separate species. Ring species complexes like this are a nightmare for taxonomists. However they are a brilliant, if rare, demonstration of the fuzziness of evolution and how gradual changes can accrue almost imperceptibly over space and/or time.
Day 41: Inca tern - Larosterna inca
Movember
The Inca tern is a beautiful tern from the coasts of Peru and Chile. The bright-white moustache of the Inca tern gives it a unique look among the terns but otherwise its ecology is representative of the tern family Sternidae. The terns are able fliers with very long, tapered wings and tails. Flight is very important to the terns for two main reasons. Firstly, terns spend a great deal of the time on the wing, using their keen eyes to spot fish before plunging from a height to seize their prey in their sharp beaks. Secondly, many terns are migratory with the Arctic tern (Sterna paradisaea) travelling up to 91,000 km each year. Though I have not seen Inca terns in the wild they do form part of the unnatural bird community found in Living Coasts Zoo and Aquarium in Torquay, a fantastic attraction which gives close looks of many overlooked but fantastic coastal animals.
Day 42: Atlantic puffin - Fratercula arctica
Friar of the cliffs
Puffins! If you do not know what a puffin is then you live in a burrow (much like a puffin) and if you don't love puffins then you have a heart of stone. One of our most charismatic birds, the puffin is famous for its bright bill and pompous gait as it struts around the grassy knolls of rocky coastlines. The colourful beak that we know and love only looks like this during the breeding season when pairs return to land to breed. The bright colours are used to signal dominance whilst couples court by rattling their beaks together in 'billing' courtship displays. In winter the beak shrinks and becomes grey in colour as individuals live a largely solitary existence on the open ocean.
The word puffin derives from the Middle English 'poffin' which actually referred to the cured carcasses of Manx shearwaters (hence Puffinus puffinus) which were originally known as Manx puffins. The word later came to describe the puffins we know, perhaps because they nest in burrows as Manxies do. Otherwise they are very different, especially when it comes to locomotion. Whilst shearwaters can traverse huge distances with relative ease, puffins have very short wings which are well adapted for swimming but terrible for flight. Their swimming ability meant that puffins were thought to be part fish, part bird, a loop-hole which allowed Catholics to eat them on Fridays and during Lent!
The Atlantic puffin shares the genus with two other puffin species whose name Fratercula refers to their resemblance to little friars. The puffins are part of the auk family (Alcidae), a relatively small group of piscivorous sea birds. Cliffs in the UK can be populated with thousands of auks and other seabirds which form classist tower-blocks. Guillemots (Uria aalge) occupy the majority of the cliff face with the chunkier razorbills (Alca torda) cramming in above. The kittiwakes (Rissa tridactyla), small, gentile gulls, take the steepest part of the cliffs whilst shags (Phalacrocorax aristotilis) live nearest the waves. Above them all, the puffins share the cliff tops with tube-nosed fulmars (Fulmaris glacialis) and nocturnal Manxies. These seabird stacks show vertical niche stratification both on the cliffs and under the water where their diving abilities determine what prey different species can access. Of all the seabirds, auks have forsaken their flying ability in favour of increased diving ability with Uria guillemots reaching down to 100 m. Of these so-called 'northern penguins', one auk went so far as to lose flight altogether but this, as with many flightless birds, would be its downfall. The great auk (Pinguinus impennis) was hunted to extinction in the mid 19th century.
