Monday, March 28, 2011

Marsh Harriers on the move

Marsh Harriers are now reaching their peak, the early waves dominated by males.

Today several birds that came over Gibraltar were mobbed by the local gulls, providing opportunities to observe their escape and defence strategies as captured in these images.

Sunday, March 27, 2011

One of those mornings!

After days of cloud and strong easterlies the morning was soon sunny once the early morning cloud had dissipated. The wind was fresh from the north-west so there was a good chance that raptors would come over Gibraltar. Early indications were good - a strong passage of Swallows, House Martins, Goldfinches, Linnets and Serins, all arriving across the Strait of Gibraltar from Morocco. With them were the first Black Kites. But the day belonged to the Booted Eagles (above and below).

These eagles are now hitting their peak passage and many had obviously been waiting to get across

The finches continued to swarm. A flock of ten or so Red-rumped Swallows dashed past a metre away from me and Bee-eaters swarmed as they noisily passed north. If the day was the Booted Eagles', the Sparrowhawks weren't far behind, darting into the trees and having a go at the passing finches. There were many males in today's migration (below).

The range of species was good and included Montagu's and Marsh Harriers.

Male Marsh Harrier overhead

Some Short-toed Eagles are still coming through - their peak was earlier in the month - and the gulls still make them feel unwelcome!

And of course the Black Kites keep on coming, these are now heading for Western and Central Europe

Wednesday, March 23, 2011

Denizens of the White Water

The fast-flowing mountain streams of the Iberian Peninsula, from the Pyrenees down to the Betics, are home to specialists at living amidst torrents and cataracts. No species is more at home here than the Dipper.

This amazing bird is widespread across the Palaearctic Region to the Himalayas. To the east it is replaced by the Brown Dipper. The American Dipper is the North American counterpart, reaching south to Central America. Two other species - White-capped and Rufous-throated - take over in South America. And that is it. There are only five species of Dipper in the world!

Dippers are highly specialised and adapted for taking insect larvae and other invertebrates under water. They don't dive for them but instead walk under water to take their prey, a unique behaviour among birds. The images below show this amazing behaviour...

Often associated with similar habitats is the beautiful Grey Wagtail, with its safrron yellow rump and undersides. It is less restricted to fast flowing streams but is usually found wherever there are Dippers.

Also present alongside is the White Wagtail but this species is the least specialised of the three and is often at home in other aquatic habitats too (below)

Perhaps more appropriately grey than the Grey Wagtail the absence of yellow separates this species easily from its cousin (below)

Saturday, March 5, 2011

Mass arrivals of Black Kites

The Black Kite is among the earliest of spring migrants and certainly the most abundant, tens of thousands crossing the Strait of Gibraltar from Morocco into Europe (below). The first ones appear in January and passage is substantial in February, building towards a peak in the first days of March.

View of the Strait of Gibraltar from the north. The mountain on the right is Jebel Musa in Morocco. The Rock of Gibraltar (in Europe) stands out on the left.

Having already undertaken the arduous crossing of the Sahara Desert, these soaring birds have to run the gauntlet of the Strait. It may not be a huge distance (only 14km at the narrowest) but flying over the sea is never good for a soaring bird. Additonally, unpredictable winds add to the hazard.

Travelling in flocks helps with keeping on the right track and offers protection. Flocks descend to roost together at night. But the downside is that wherever they stop there is unlikely to be sufficient food to feed them all. So they tend to fast during the journey, catching prey opportunistically when the chance arises, and simply get on with the migration as quickly as possible.

The early birds are the ones from the south. They will breed in southern Iberia. As the season advances birds heading further north arrive. These may be going all the way to Switzerland, Germany and France. One the breeding adults have passed, a second movement - of immatures - takes place between late April and June. All in all, almost six months of Black Kite migration!