Tuesday, June 29, 2010


The breeding seabirds that we have been looking at in recent posts share one thing in common: they all breed on rocky cliffs and islands from which they foray out to sea to catch their prey. The Guillemot is a perfect example: they nest in tight colonies in very confined space, situations that territorial birds would not tolerate. But food is dispersed at sea so the advantage in nesting all packed lies in protection from predators and is an inevitability anyway as safe nesting sites are discretely spaced out. So the Guillemots in the Farnes fly out to sea where they hunt in packs.

the prize is brought back home

the nest is barely a smattering of vegetation so the egg is in real danger of being knocked over the narrow ledge, especially in such packed colonies. So the Guillemot's egg is conical which ensures that the egg spins on its apex and stays in the nest. The risk of loss is minimised.

with luck, the chicks hatch and a new generation comes to the world

...but the troglodyte experience is not limited to seabirds. Next we will look at a different kind of colonial rock dweller - some vultures and other birds of prey nest on inland cliffs and rock islands, and they too breed in close proximity and venture far and wide away from the colony in flocks in search of dispersed food. When we see patterns emerging among distantly related species and with apparently different behaviours we discover the inner beauty of Nature.

Thursday, June 17, 2010

In the heat of the midday sun

One of the most beautiful of gulls is, in my opinion, the Kittiwake or, as now known, Black-legged Kittiwake. This bird breeds in the North Atlantic and disperses south to the waters around the Strait of Gibraltar and even further down the Atlantic coast of North Africa. But its winter numbers are heavily dependent on weather conditions. If we get long periods of severe south-westerlies, then many birds that are wintering out at sea in the Atlantic get pushed inshore. During such times many get beached and die. I remember years with tens of thousands of Kittiwakes around our coasts in December and January, even as late as March.

We find fossil Kittiwakes in our caves, going back 50 thousand years. It is possible that many more came down to winter here during the glacial periods but the numbers of this and other seabirds suggests that they may even have bred in these latitudes. It is tempting to imagine colonies of Kittiwakes on the cliffs of the Rock of Gibraltar, just as we find them on the Farnes today.
Even in high latitudes, Kittiwakes nesting in exposed rock ledges suffer the heat of the midday sun on warm days. What would they have done in the strong sun of lower latitudes, even during glacials?
Adults and chicks panting hard to lose heat

adult trying to shade a chick

chicks' dilemma - do I eat or keep cool?

perhaps an afternoon siesta is the solution...

Wednesday, June 16, 2010

A bird that's always been there

I grew up with the familiar sight of European Shags flying along the Gibraltar coastline. A few pairs still breed here, maybe no more than 6 close to the palaeontological and archaeological site of Gorham's Cave on the eastern side of the Rock. They are about the only ones left breeding on the Mediterranean  mainland coast of Iberia. These birds are of the Mediterranean race desmarestii and have been around for as long as our evidence can relate. Yes, in the very caves I have mentioned we have excavated the bones of this bird going back to over 50 thousand years ago! Now that's heritage!

The birds that I am illustrating here belong to the Atlantic race aristotelis and were photographed in the Farne Island seabird colonies that I have been describing in recent posts. Here they breed on sheer cliff ledges where they lay their eggs on nests made of sticks and twigs. And it is in these that they raise the ungainly chicks.

The European Shag is a truly Western Palaearctic bird and is not found outside this region. The birds live in mild oceanic and Mediterranean coasts and are largely resident. Unlike the larger Great Cormorant these birds hardly venture away from seacoasts into inland waters. They have survived on our coasts for 50 thousand years at least but the last mainland Iberian Mediterranean colony is feeling the pressure of isolation more and more. If we are not careful we may be talking of a locally extinct species in the not too distant future. Let's hope that they continue to show the resilience that has kept them going this far.

Monday, June 14, 2010

In the heart of a ternery

If you're into bird migration then the Arctic Tern, the greatest of travellers, must be high on your list of favourites. Many migratory birds perform gargantuan feats of travel but the Arctic Tern breeds in the northern hemisphere, close to the Arctic Circle, and winters in the Antarctic. This bird lives in a perpetual summer!

Arctic Terns nest in large colonies which are a spectacle to visit. These little terns are strongly defensive of their nests and attack anyone on sight. Hats are advisable when visiting a ternery. During this visit to the Inner Farne colony Arctic Terns concentrated on pecking Geraldine's knuckles (the only part exposed as she took photographs) and drew blood! Still all was worth it for the photographs taken...

under attack!

On islands with rich fishing offshore, terneries may have more than one species breeding. Here we had Arctic Terns (above) and smaller numbers of Common Terns (below).

and sticking together in a separate part of the island is a colony of the larger Sandwich Tern (above and below).

Black-headed Gulls nest scattered between the terns and opportunistically try to rob them of their food. Not surprisingly the terns mob them when they are not busy attacking humans.

but it is the Arctic Terns that are stars of the show, and they make sure you know it!

but you know when you've had enough and the terns have won!

and they all come out to make sure you don't return!

Saturday, June 12, 2010

A Bird out of Prehistory

One of my favourite seabirds is the Razorbill. Not as well known, or photographed, as the Puffin the Razorbill is a magnificant bird especially when seen at close quarters. Unlike the Puffin, which nests in burrows, the Razorbill lays its single egg on a precarious cliff ledge and it is here that the young chick is raised.

Down here in the Strait of Gibraltar I see more Razorbills than Puffins in the winter. That is because these birds feed in shallower water than the Puffins and so they will fish in sheltered bays and coasts on the European coast. The Puffin feeds in deeper water and the North African coast is better suited to them. It is in March and April that I see tens of thousand of both species exiting the Mediterranean on their way back to the breeding grounds. Razorbills generally pass ahead of Puffins. But I never get to see these birds close-up in the splendour of their breeding plumage.
On the Farnes Razorbills are much less abundant than Puffins. Fewer than 200 pairs breed on the two islands that we visited but it was a real treat to see them so well.
Razorbills mix with other auks, especially the larger Guillemots, in offshore rafts in search of fish.
This bird reminds me of a sadly extinct auk, the Great Auk, which reached these shores during the Pleistocene and was hunted to extinction globally with the last ones killed as recently as the 19th Century.
Today, I'm going to ask followers of this blog to have a close look at this bird. I wonder how many of you may find that the elegance of this bird surpasses the colours and comical look of the popular Puffin. Take a close look and compare with the Puffins of the post of 8th June. Do give your opinion!