Wednesday, 1 February 2017

Spain 17: Choughs

Red-Billed Chough, Ireland
Across Eurasia can be found two species of distinctive crows that are distinguished by the colour of their beaks, the Red-Billed and Alpine (or Yellow-Billed) Choughs. They are associated with short grass and rocky areas, especially mountains. Red-Billed Choughs Pyrrhocorax pyrrhocorax also use sea cliffs while Alpine P. graculus is only found in high mountains. They are rather distinctive crows and in some ways their ecology is similar to some starlings, although starlings are on a completely different branch of the passerine family tree.

Alpine Chough. note Yellow Bill This was taken on the Zugspitze, Bavaria at nearly 3000m
The diet of choughs of both species is heavily geared towards invertebrates of various kinds. These may be picked off the surface of short grass or dug for by probing in the ground. Plant material is also taken and Alpine in particular will scavenge or take any other food available, which is why they often hang around ski resorts for scraps. Alpine will often feed on berries, including Juniper berries, while Red-Billed tends to dig for bulbs.
Red-Billed in Flight
Both species nest in holes or crevices in cliffs or similar situations. This includes buildings, especially abandoned ones, but dams or quarries are also used. The clutch size is between 3 and five eggs. Fledging takes around 30 days for the slightly smaller Alpine, around 40 for Red-Billed. Although neither species is strictly colonial they are highly sociable and juveniles learn feeding areas from their peers and other adults.
Alpine in flight. Note longer tail than Red-Billed.
Although the global status of both species is listed as Least Concern there have been declines in both species as a result of changes in farming practise in western Europe in particular, which reduces the short grazed grassland they need as foraging areas. Climate change may also affect the distribution in future, especially for the more specialised Alpine Chough. Alpine in known from subfossil remains from Tenerife but they are now extinct there, although Red-Billed can still be found on the Canary Islands. The extinction of Alpine from Tenerife may be due to natural causes – living only at altitude on an active volcano is not exactly conducive to long term survival.

In Spain we only came across Alpine Chough once, flying above a ski resort on the French border. Red-Billed were far more widespread and we saw them most days.

In the British Isles we have an endemic subspecies. Formerly widespread around the coasts where livestock grazing provided suitable feeding areas, changes in farming practise resulted them disappearing from England, with the last successful breeding in Cornwall in 1947 and the last birds actually seen in 1973. However, in 2001 a small group spread back to Cornwall from Ireland and from 2002 onwards they have bred successfully. Good sites to see them are the Lizard peninsula and around Land’s End. These birds feature prominently in Cornish folklore, and one story accuses them of frequently starting fires by taking coals from a fire or oven and dropping them in thatched houses or haystacks. This may be related to the habit of many birds of “anting” when they expose themselves to ants or deliberately pick them up and rub them over their feathers for unknown reasons. I have seen film of birds using smoke from fires in the same way and this may be where the story started.

For more on the Cornish Choughs see here:

(Red-Billed images from Wikipedia, Alpine Chough images my own)

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