Friday, March 12, 2010

The Ivy Magnet

I've been keeping an eye on some Ivy in the museum garden as its fruit were ready to ripen. No sooner did they become ripe than they attracted local and migratory birds. The two main species were Blackcap and Blackbird, both now breeding in Gibraltar. It gave me an opportunity to photograph two species which are noticeably different from their European cousins.

Notice how dark these birds are, especially on the belly and flanks, compared to western and central European birds which are migrants down here. Notice also how short the wing is relative to the tail. In fact, when I studied these birds in the 1970s I found that they had a very different wing formula. Their wings are not only shorter, they are more rounded. Currently the best classification for these birds is to put them under the subspcies Sylvia atricapilla heineken which would include those in south-west Iberia, Madeira and the Canary Islands.

Migrant Blackcap (above) for comparison with local birds (from 19th February post). Competition between Blackcaps, especially the males, was severe around the ivy. In some cases migrants and local Blackcaps chased each other away from the precious food resource. Meanwhile the ivy was getting its way - its seeds were being dispersed!

The local Blackbirds are also distinct from their European counterparts, expecially the females that are very grey with yellow bills. They have very short, rounded, wings too and are also resident. They resemble the North-African subspecies Turdus merula mauritanicus. They are also breeding now and are very fond of the ivy.

Female Blackbirds (above and below)

Male Blackbirds (above and below)

Blackbird shakes its head vigorously while holding onto fruit to dislodge it (above). Spotless Starlings (below) are also getting attracted to the ivy and a nearby palm.

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