Red Crossbill
Loxia curvirostra

>> GENERAL >>>>>

– medium-sized passerine, slightly larger than Common Chaffinch– diurnal migrant
– migrates singly or in small to medium loose flocks
– annual post-breeding migration and in years of crop-shortfalls massive invasion events
– Pine sp. related populations are thought to be sedentary, especially those from Southern Europe, therefore are omitted here

>> VISUAL ID >>>>>

– several subspecies and so called ecomorphs with different measurements but also subtle to obvious differences in colouration and vocalisations (see below) occur
– most ecomorphs can only be distinguished in hand


Red Crossbill Loxia curvirostra ssp., AD M
BIF2013, 01/03/2014, Werdauer Forst, Germany, Jens Halbauer
– AD M unmarked strawberry red exept for blackish wings and tail and light grey undertail coverts


Red Crossbill Loxia curvirostra ssp., M
BIF2144, 14/02/2018, Rostock, Germany, Roland Neumann
– conspicuously long and pointed wings
– dark underwing coverts


Red Crossbill Loxia curvirostra ssp., M
BIF2144, 14/02/2018, Rostock, Germany, Roland Neumann
– note different shape of the tail when fanned out


Red Crossbill Loxia curvirostra ssp., F
BIF2134, 03/08/2013, Hof, Germany, Mathias Putze
– F greyish with olive on breast and upper belly
– in straight flight rather short, distinctly forked tail
– fairly large-headed


Red Crossbill Loxia curvirostra ssp., F
BIF2135, 03/08/2013, Hof, Germany, Mathias Putze
– large bill


Red Crossbill Loxia curvirostra ssp., M
BIF2136, 06/02/2018, Rostock, Germany, Roland Neumann
– in M the blackish wings and tail are contrasting to the shining red rump
– reasonable aging in flight is impossible


Red Crossbill Loxia curvirostra ssp.
BIF2137, 06/02/2018, Rostock, Germany, Roland Neumann
– dense flocks, usually consisting of both sexes

>> ACOUSTIC ID >>>>>

– very vocal
– most often to be heard is the so called flight call
– sometimes single birds or flocks also utter excitement calls during long distance flights
flight calls are on average 0,05-0,1s in length
– the frequency band of the 1st partial is between 2-6kHz
flight calls show evenly spaced inharmonic partials, but are different in different call types
– several ecomorphs –often referred to as call types– with different vocalisations occur
– every ecomorph is thought to have one distinct flight call and one corresponding excitement call
– mismatched flight and excitement calls are thought to be very rare exceptions
– some authors disagree in that and report birds with different combinations or even more than one corresponding excitement call (e.g. SUMMERS et al. 2002)
– most widespread call types comprise numerous local dialects
flight calls also show (individual) variation at least due to call matching between partners,
families and probably migrating flocks (as in the closely relative Redpolls)
– JUV’s are supposed to individually recognise their parents based on those matched calls (MÜNCH 2003)
– JUV flight calls show obvious plasticity, but just for a very short period of time
– calls are learned from parents or other conspecifics near nest
– in some call types, excitement calls seem to be (almost) identical
– at different stages of excitement, excitement calls can vary considerably
– separation between ecomorphs is supposed to be stable due to assortative mating
ecomorphs with ‘wrong’ call types (even of other crossbills species) are very rare exceptions
– most call types are not necessarily linked to particular subspecies
– different ‘systematics’ to recognise all call types and their variations have been introduced (ROBB 2000, SUMMERS et al. 2007, FÖRSCHLER et al. 2009, CLOUET 2015, MARTIN et al. 2019)
– more undocumented ecomorphs, call types and dialects probably occur
– more solid research, especially of individually marked birds, is necessary

TYPE A

calls in flight not yet sound recorded

TYPE B
– the flight call has undergone some change since Robb (2000) described it
generally rather invariable (see above for exceptions)


Red Crossbill Loxia curvirostra ssp., type B, AD M, AD F, JUV, flight call, excitement call
BIF2261, 22/05/2018, Důl Bílého Labe, Czech Republic, Patrick Franke
– local breeding population


Red Crossbill Loxia curvirostra ssp., type B, flight call
BIF1987, 02/02/2018, Werdauer Forst, Germany, Patrick Franke


Red Crossbill Loxia curvirostra ssp., type C, M, flight call
BIF1990, 17/02/2015, Šumava National Park, Czech Republic, Patrick Franke
– maybe extreme variation of type B (documented mixed pair male type C and female type B)
– a rather local breeding population

TYPE C
– has the largest distribution area, with many local dialects and variations

Red Crossbill Loxia curvirostra ssp., type C, flight call
BIF2018, 13/08/2017, Sachsendorf, Gemrany, Patrick Franke


Red Crossbill Loxia curvirostra ssp., type C, flight call
Goldcrest Regulus r. regulus, flight call
Marsh Tit Poecile p. palustris, call

BIF1986, 02/12/2014, Werdauer Forst, Germany, Patrick Franke
– maybe extreme variation of type C

TYPE D
– only unobvious variations (see above for exceptions)
– but a second, rather invariable form has increasingly been recorded in Central Europe in recent years (BIF2021) often considered as a different type or the current Type B


Red Crossbill Loxia curvirostra ssp., type D, AD M, flight call
BIF1998, 01/03/2014, Werdauer Forst, Germany, Patrick Franke


Red Crossbill Loxia curvirostra ssp., type D, flight call
Blue Tit Cyanistes c. caeruleus, call
Yellowhammer Emberiza c. citrinella, call

BIF2257, 02/02/2018, Werdauer Forst, Germany, Patrick Franke


Red Crossbill Loxia curvirostra ssp., type D, flight call
BIF2021, Garmisch-Partenkirchen, Germany, Michèle Peron

TYPE E
– the flight call has undergone a slightly change since Robb (2000) described it
– with some local dialects and variations
– it is widespread to consider this type as the current form of Type A


Red Crossbill Loxia curvirostra ssp., type E, flight call
Stock Dove Columba o. oenas, song

BIF1997, 14/07/2017, Werdauer Forst, Germany, Patrick Franke


Red Crossbill Loxia curvirostra ssp., type E, flight call
BIF1996, 16/07/2017, Terpitz, Germany, Patrick Franke

TYPE F

calls in flight not yet sound recorded

TYPE X
– the flight call has undergone some change since Robb (2000) described it
– generally rather invariable (see above for exceptions)


Red Crossbill Loxia curvirostra ssp., type X, flight call
BIF2011, 14/07/2017, Werdauer Forst, Germany, Patrick Franke


Red Crossbill Loxia curvirostra ssp., type X, flight call
BIF2260, 04/03/2018, Reudnitz, Germany, Patrick Franke


Red Crossbill Loxia curvirostra ssp., type X, JUV, flight call
BIF2010, 18/03/2014, Werdauer Forst, Germany, Patrick Franke

MIXED FLOCKS

Red Crossbill Loxia curvirostra ssp., type A C D F X, 30 IND, flight call
BIF2015, 14/07/2017, Werdauer Forst, Germany, Patrick Franke

Red Crossbill Loxia curvirostra ssp., type A C D F X, 30 IND, flight call
BIF2016, 14/07/2017, Werdauer Forst, Germany, Patrick Franke

Red Crossbill Loxia curvirostra ssp., type A C D, flight call
BIF2014, 14/07/2017, Werdauer Forst, Germany, Patrick Franke

>> COMPARISON SPECIES >>>>>

Two-barred Crossbill (v) (a)
Scottish Crossbill (v) (a)
Parrot Crossbill (v) (a)
Tree Sparrow (a)
Common Redpoll (a)
Pine Grosbeak (v)
Hawfinch (v)

#songbird #passerine #finch

#ornithology #birdmigration #birdID #birdguide #birding #birdwatching #birdsound #westernpalearctic #europe #vismig #flightcalls #middleeast #northernafrica #workinprogress

References:
Clouet M., J. Joachim 2015, Vocal Types of Common Crossbills in the Pyrenees and the Alps, Ardea
Förschler M. et al. 2009, Vocal types in crossbill populations (Loxia spp.) of Southwest Europe, Journal of Ornithology
Martin R. et al. 2019, Delimitation of call types of Red Crossbill (Loxia curvirostra) in the Western Palearctic, Ecotone
Münch H. 2007, Die Kreuzschnäbel, Westarp Wissenschaften
Robb M. S. 2000, Introduction to vocalizations of crossbills in north-western Europe, Dutch Birding 22
Summers R.W. et al. 2002, The distribution and habitats of crossbills Loxia spp. in Britain, with special reference to the Scottish Crossbill Loxia scotica, Ibis