Scottish Crossbill (Loxia scotica) [XC606514]
by Peter Stronach from , United Kingdom (call, chitters)
Scottish Crossbill (Loxia scotica) [XC821424]
by Peter Stronach from , United Kingdom (call)
Nest
A twig platform, usually close to the trunk of a tree.
Eggs (Guide)
4; off-white with bold spots or reddish-brown.
Subspecies
No subspecies.
Forms a species group with Red Crossbill (Loxia curvirostra) and Parrot Crossbill (Loxia pytyopsittacus), and all have sometimes been considered conspecific. Present species almost identical to Red Crossbill (Loxia curvirostra) in wing, tail, bill and tarsus measurements, and overlaps in wing and bill measurements with Parrot Crossbill (Loxia pytyopsittacus). Intermediate between those two species in bill shape (a feeding adaptation), and feeding behaviour (and excitement call) apparently sufficient partly to isolate it from Red Crossbill (Loxia curvirostra), no hybridization known in slight overlap in breeding ranges. Recently found to hybridize with Parrot Crossbill (Loxia pytyopsittacus), and genetic evidence reveals limited differences between the three species in Europe, indicating that they are not in total reproductive isolation. Studies of breeding (of captive and wild populations) reveal assortative mating principally on basis of bill size and flight and excitement calls, but extent of hybridization not fully known and differences, although slight, are sufficient to restrict widespread interbreeding. Further research is required.
The Reader's Digest Book of British Birds 1980, 3rd Edition, Drive Publications Ltd ISBN 0 340 25308 8
Birds in Colour Campbell, B., 1960, Penguin Books Ltd
The Pocket Guide to Nest and Eggs Fitter, R.S.R., 1954, Collins
RSPB Handbook of British Birds Holden, P., Cleeves, T., 2002, A & C Black ISBN 0 7136 5713 8
Birds of Britain and Europe Sterry, P., et al., 2001, AA Publishing ISBN 0 7495 3068 5
The Popular Handbook of British Birds Hollom, P.A.D., 1973, H.F. & G. Witherby Ltd ISBN 0 85493 002 7
BirdLife International Species Factsheet