– medium-sized passerine, a bit larger in size than Common Chaffinch<\/a> >> FLIGHT >>>>><\/strong> > VISUAL ID >>>>><\/strong><\/p>\n >> SOUND ID >>>>><\/strong><\/p>\n – very vocal – several populations with different flight and excitement calls exist, so-called call types<\/em> Listed below, the most common call types of northern and central Europe:<\/strong><\/p>\n TYPE A GROUP
\n– diurnal migrant
\n– annual post-breeding migration
\n– in years of crop-shortfalls massive invasion events (influx)
\n– pine related populations are thought to be sedentary, especially those from Southern Europe, therefore are omitted here
\n– several subspecies but also so called ecomorphs<\/em> with different measurements but also subtle to obvious differences in colouration and vocalisations (see below<\/em>)
\n– very eager to call on migration, therefore clearly identifiable among other finches<\/p>\n
\n– appears quite stocky with a short tail in flight
\n– migratory flocks usually comprise 1-20 individuals, sometimes more, especially in invasion years and at migration hotspots
\n– flight fast, straight, little hopping<\/p>\n![\"\"](\"https:\/\/birds-in-flight.net\/wp-content\/uploads\/2018\/02\/BIF2013_JHA_01032014_rcbill-1-AD-M_d_sn_werdau-1024x683.jpg\")
<\/a>
\nRed Crossbill Loxia curvirostra <\/em>ssp., AD M<\/strong>
\nBIF2013, 01\/03\/2014, Werdauer Forst, Germany, Jens Halbauer
\n– AD M unmarked strawberry red exept for blackish wings and tail and light grey undertail coverts<\/p>\n![\"\"](\"https:\/\/birds-in-flight.net\/wp-content\/uploads\/2018\/02\/BIF2144_RNE_13022018_RCbill-M_Rostock-1024x683.jpg\")
<\/a>
\nRed Crossbill Loxia curvirostra <\/em>ssp., M<\/strong>
\nBIF2144, 14\/02\/2018, Rostock, Germany, Roland Neumann
\n– conspicuously long and pointed wings
\n– dark underwing coverts<\/p>\n![\"\"](\"https:\/\/birds-in-flight.net\/wp-content\/uploads\/2018\/03\/BIF2207_RNE_06022018_RCbill-MF_Rostock-1024x683.jpg\")
<\/a>
\nRed Crossbill Loxia curvirostra <\/em>ssp., M<\/strong>
\nBIF2144, 14\/02\/2018, Rostock, Germany, Roland Neumann
\n– note different shape of the tail when fanned out<\/p>\n![\"\"](\"https:\/\/birds-in-flight.net\/wp-content\/uploads\/2018\/02\/BIF2134_MPU_I1Q0004_03082013_loxcur_F_d_hof-1024x683.jpg\")
<\/a>
\nRed Crossbill Loxia curvirostra <\/em>ssp., F<\/strong>
\nBIF2134, 03\/08\/2013, Hof, Germany, Mathias Putze
\n– F greyish with olive on breast and upper belly
\n– in straight flight rather short, distinctly forked tail
\n– fairly large-headed<\/p>\n![\"\"](\"https:\/\/birds-in-flight.net\/wp-content\/uploads\/2018\/02\/BIF2135_MPU_I1Q0008_03082013_loxcur_F_d_hof-1024x683.jpg\")
<\/a>
\nRed Crossbill Loxia curvirostra <\/em>ssp., F<\/strong>
\nBIF2135, 03\/08\/2013, Hof, Germany, Mathias Putze
\n– large bill<\/p>\n![\"\"](\"https:\/\/birds-in-flight.net\/wp-content\/uploads\/2018\/02\/BIF2136_RNE_06022018_RCBill_Rostock-1024x682.jpg\")
<\/a>
\nRed Crossbill Loxia curvirostra <\/em>ssp., M<\/strong>
\nBIF2136, 06\/02\/2018, Rostock, Germany, Roland Neumann
\n– in M the blackish wings and tail are contrasting to the shining red rump
\n– reasonable aging in flight is impossible<\/p>\n![\"\"](\"https:\/\/birds-in-flight.net\/wp-content\/uploads\/2018\/02\/BIF2137_RNE_06022018_RCBill_Rostock-1024x683.jpg\")
<\/a>
\nRed Crossbill Loxia curvirostra <\/em>ssp.<\/strong>
\nBIF2137, 06\/02\/2018, Rostock, Germany, Roland Neumann
\n– dense flocks, usually consisting of both sexes<\/p>\n
\n– most often to be heard during migration is the flight call<\/em>
\n– sometimes single birds or flocks also utter excitement calls<\/em>
\n– flight calls<\/em> are on average 0,05-0,1s in length
\n– the frequency band<\/em> of the 1st partial<\/em> is between 2-6kHz
\n– flight calls<\/em> show evenly spaced inharmonic partials<\/em>, but are different in different call types<\/em><\/p>\n
\n– each population is thought to have one unique flight call<\/em> and a corresponding excitement call<\/em>
\n– mismatched flight and excitement calls are thought to be very rare exceptions
\n– some authors disagree in that and report birds with different combinations or even more than one corresponding excitement call<\/em> (e.g. SUMMERS et al. 2002)
\n– bilingual birds are thought to be very rare exceptions too
\n– flight calls<\/em> show (individual) variation at least due to call matching<\/em> between partners,
\nfamilies and probably migrating flocks (as in the closely relative Redpolls<\/a>)
\n– JUV’s are supposed to individually recognise their parents based on those matched calls (M\u00dcNCH 2003)
\n– JUV flight calls<\/em> show obvious plasticity, but just for a short period of time (up to a few weeks)
\n– calls are learned from parents or other conspecifics near nest
\n– excitement calls<\/em> seem to be (almost) identical in different in some call types<\/em>
\n– at different stages of excitement, excitement calls<\/em> can vary considerably
\n– call types<\/em> are supposed to be stable due to assortative mating
\n– Red Crossbills uttering call types of other crossbills species are very rare exceptions
\n– call types<\/em> are not linked to particular subspecies
\n– different ‘systematics’ to recognise all call types<\/em> and their variations have been introduced (ROBB 2000, SUMMERS et al. 2007, F\u00d6RSCHLER et al. 2009, CLOUET 2015, MARTIN et al. 2019)
\n– more undocumented call types<\/em> and variants<\/em> most likely occur
\n– more solid research, especially of individually marked birds, is necessary<\/p>\n
\n<\/strong>– it is widespread to consider this type has considerably ‘morphed’ into a type E like shape
\n– type A and type E still exist in shapes and variations described by M. Robb (2000)
\n– breeding range restricted to N-England and Scotland<\/p>\n