Friday, 2 May 2014

Quest for the Wild Canary 11: Larger Passerines

Common Raven
There is a wide variety of endemic or near-endemic passerines on the Canaries, but the most prominent large bird to be seen is the very widespread Common Raven. This is of a different race to the form found in Britain, and is classified as Corvus corax tingitanus, which is the same subspecies as is found across North Africa, and has a higher pitched call than the nominate subspecies. As a generalist and adaptable feeder, it must be a major nest predator of all species both native and introduced, and no doubt also feeds at rubbish tips or anywhere else food can be found. The one I photographed here was hanging around a coach stop on Fuerteventura and was obviously used to being fed by tourists.

Red-Billed Chough
Currently, there is only one other corvid breeding on the Canaries, although several species are known as rare vagrants. Red-Billed Chough Pyrrhocorax pyrrhocorax currently only breeds on Las Palma, where there is a population of around 3-400 pairs. However, they are heavily dependent on human modified habitats and it is not impossible they derive from human introduction. Against this, remains of Red-Billed Chough are known from several islands, so at one time they were genuine natives and widespread across the islands. The Las Palma birds are classes as P.pyrrhocorax barbarus, which is also found in North Africa.

Alpine Chough
 The more high-altitude loving Alpine Chough Pyrrhocrax graculus is also known from subfossil remains on Las Palma and Tenerife, but is not known on the islands today. Both the Choughs probably colonised as some time during an ice age, when they were more widespread in both Europe and Africa.

Canary Great Grey Shrike
The other predatory passerine to be found on the islands is the Canary Great Grey Shrike, Lanius excurbitor koenigi. We found these on both Tenerife and Fuerteventura, and they also occur on other islands in the group. The taxonomy of these shrikes is in a certain amount of flux – the Grey Shrike complex has a worldwide distribution and depending on how you define a species the birds on the Canaries may be a race of Southern Grey Shrike L.meridionalis, a race of African Grey Shrike L.elegans, or even a species in their own right as L.koenigi. Either way, they seem to be doing OK at present – the first ones we saw were on a patch of rough ground in the middle of town. Incidentally, this means that a shrike which is relaxed around people may not necessarily be an escape – such birds are in any case very rare as captive birds – it may just be used to living in populated areas.
(Images of choughs from Wikipedia, others are my photos)

No comments:

Post a Comment