>> GENERAL >>>>>
– medium-sized passerine, a bit larger in size than Common Chaffinch
– diurnal migrant
– annual post-breeding migration
– in years of crop-shortfalls massive invasion events (influx)
– pine related populations are thought to be sedentary, especially those from Southern Europe, therefore are omitted here
– several subspecies but also so called ecomorphs with different measurements but also subtle to obvious differences in colouration and vocalisations (see below)
– very eager to call on migration, therefore clearly identifiable among other finches
>> FLIGHT >>>>>
– appears quite stocky with a short tail in flight
– migratory flocks usually comprise 1-20 individuals, sometimes more, especially in invasion years and at migration hotspots
– flight fast, straight, little hopping
> VISUAL ID >>>>>
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
>> SOUND ID >>>>>
– very vocal
– most often to be heard during migration is the flight call
– sometimes single birds or flocks also utter excitement calls
– 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 populations with different flight and excitement calls exist, so-called call types
– each population is thought to have one unique flight call and a 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)
– bilingual birds are thought to be very rare exceptions too
– flight calls 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 short period of time (up to a few weeks)
– calls are learned from parents or other conspecifics near nest
– excitement calls seem to be (almost) identical in different in some call types
– at different stages of excitement, excitement calls can vary considerably
– call types are supposed to be stable due to assortative mating
– Red Crossbills uttering call types of other crossbills species are very rare exceptions
– call types are not 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 call types and variants most likely occur
– more solid research, especially of individually marked birds, is necessary
Listed below, the most common call types of northern and central Europe:
TYPE A GROUP
– it is widespread to consider this type has considerably ‘morphed’ into a type E like shape
– type A and type E still exist in shapes and variations described by M. Robb (2000)
– breeding range restricted to N-England and Scotland
Red Crossbill Loxia curvirostra ssp., putative type A or (S5), flight call
BIF3652, 16/12/2015, Mt. Boubin, Czech Republic, Patrick Franke
– here in a rather unusual shape, maybe due to call matching during breeding period
– the upper right element is typical for Southern European call types, thus this call might be just very similar to Type A
TYPE B GROUP
– very variable, as shown by Magnus Robb (2000)
– quite similar to Type D, most likely belongs to the same group
– the dominant breeding population in the Northern Alps
Red Crossbill Loxia curvirostra ssp., type B (N1), flight call
BIF2021, Garmisch-Partenkirchen, Germany, Michèle Peron
TYPE C GROUP
– the generalist among eurasian crossbills, widespread from Western Europe E to Japan
– nevertheless, shape has considerably changed during the last decades
– some variations occur, even in Europe
Red Crossbill Loxia curvirostra ssp., type C (N4), flight call
BIF2018, 13/08/2017, Sachsendorf, Germany, Patrick Franke
– the classic type C shape
Red Crossbill Loxia curvirostra ssp., putative type C (N9), flight call
BIF1994, 14/07/2017, Werdauer Forst, Germany, Patrick Franke
– obviously belongs to the type C group, despite very different excitement call
– used to be called Typ ISO in the past
Red Crossbill Loxia curvirostra ssp., putative type C (N5), flight call
Goldcrest Regulus r. regulus, flight call
Marsh Tit Poecile p. palustris, call
BIF1986, 02/12/2014, Werdauer Forst, Germany, Patrick Franke
– maybe an extreme variation of type C
Red Crossbill Loxia curvirostra ssp., type C (N11), AD M, AD F JUV, flight call, excitement call
BIF2261, 22/05/2018, Důl Bílého Labe, Czech Republic, Patrick Franke
– included into type B by Magnus Robb (2000) based on the very different excitement call
– considering the flight call only, clearly belongs to the type C group
– related to Black & Mountain Pine
Red Crossbill Loxia curvirostra ssp., type C (N11), flight call
BIF1987, 02/02/2018, Werdauer Forst, Germany, Patrick Franke
Red Crossbill Loxia curvirostra ssp., type C (N11), M, flight call
BIF1990, 17/02/2015, Šumava National Park, Czech Republic, Patrick Franke
– another rather extreme variation, maybe due to call matching during the breeding period
– typical chitter calls of this variation in background
TYPE D GROUP
– widespread
– only unobvious variations within this group
Red Crossbill Loxia curvirostra ssp., type D (N7), AD M, flight call
BIF1998, 01/03/2014, Werdauer Forst, Germany, Patrick Franke
Red Crossbill Loxia curvirostra ssp., type D (N7), flight call
Blue Tit Cyanistes c. caeruleus, call
Yellowhammer Emberiza c. citrinella, call
BIF2257, 02/02/2018, Werdauer Forst, Germany, Patrick Franke
– rather extreme variation, maybe due to call matching during the breeding period
TYPE E GROUP
– 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
– type A and type E still exist in shapes and variations described by M. Robb (2000)
– breeding range restricted to N-England and Scotland
Red Crossbill Loxia curvirostra ssp., type E (N3), flight call
Stock Dove Columba o. oenas, song
BIF1997, 14/07/2017, Werdauer Forst, Germany, Patrick Franke
Red Crossbill Loxia curvirostra ssp., type E (N3), flight call
BIF1996, 16/07/2017, Terpitz, Germany, Patrick Franke
TYPE F GROUP
– just exceptionally found in Central Europe
– only a single recording out of more 900+ Red Crossbill recordings in our archive
Red Crossbill Loxia curvirostra ssp., type F, flight call
BIF3347, 02/02/2018, Werdau, Germany, Patrick Franke
TYPE X GROUP
– the flight call has undergone some change since Robb (2000) described it
– generally rather invariable (see above for exceptions)
– most likely belongs to the same group as type C
Red Crossbill Loxia curvirostra ssp., type X (N8), flight call
BIF2011, 14/07/2017, Werdauer Forst, Germany, Patrick Franke
Red Crossbill Loxia curvirostra ssp., type X (N8), flight call
BIF2260, 04/03/2018, Reudnitz, Germany, Patrick Franke
Red Crossbill Loxia curvirostra ssp., type X (N8), 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