The Common Crossbill (Loxia curvirostra) is a small passerine
bird in the finch family Fringillidae. It breeds in the
spruce forests of North America, where it is known as
Red Crossbill, as well as Europe and Asia; some populations
(different species?) breed in pine forests in certain areas of all three continents, and in North
America, also in Douglas-fir. It nests in conifers,
laying 3–5 eggs.
This crossbill is mainly resident, but will regularly erupt south if its food source fails. This species will form flocks outside the breeding season, often
mixed with other crossbills.
The crossbills are characterised by the mandibles crossing at their tips, which gives the
group its English name. They are specialist feeders on conifer cones, particularly the various spruce species but also some populations (different species?) in
Douglas-fir and various pine species, and the unusual bill shape is an adaptation to assist the extraction of the seeds from the
cone.
Adult males tend to be red or orange in colour, and females green or yellow, but there is much variation.
This species is difficult to separate from Parrot Crossbill and Scottish Crossbill, both of which breed within its Eurasian range. The identification problem is less
severe in North America, where only Red Crossbill and White-winged Crossbill
occur.
Plumage distinctions from Parrot and Scottish Crossbills are negligible. The head and bill
are smaller than in either of the other species. Care is needed to identify this species. The glip or chup call is
probably the best indicator.
Work on vocalisation in North America suggest that, in that continent alone, there are eight or nine populations of Red
Crossbill with different calls, which rarely if ever interbreed. These forms also vary in terms of bill size and structure, and
specialise on the seed cones of different species of conifer. Few ornithologists seem
inclined to give these forms species status at present.
Some large-billed, pine-feeding populations currently assigned to this species in the Mediterranean area may possibly be better referred to either Parrot Crossbill or alternatively to
new species in their own right, but as yet, research into them is still at a very early stage. These include Balearic Crossbill
L. curvirostra balearica and North African Crossbill L. curvirostra poliogyna, feeding primarily on
Aleppo Pine (Pinus halepensis); Cyprus Crossbill L. curvirostra guillemardi,
feeding primarily on European black pine (Pinus nigra); and an as-yet
unidentified crossbill with a Parrot Crossbill-size bill feeding primarily on Bosnian Pine
(Pinus heldreichii) in the Balkans. These populations also differ on plumage, with the
Balearic, North African and Cyprus races having yellower males, and the Balkan type having deep purple-pink males; this however
merely reflects the differing anthocyanin content of the cones they feed on, as these
pigments are transferred to the feathers.
Crossbill Diversity
Distinct Eurasian Common Crossbill populations:
- Balearic Crossbill, Loxia curvirostra balearica
- North African Crossbill, Loxia c. poliogyna
- Corsican Crossbill, Loxia c. corsicana
- Cyprus Crossbill, Loxia c. guillemardi
- Crimean Crossbill, Loxia c. mariae
- Luzon Crossbill, Loxia c. luzoniensis
- Annam Crossbill, Loxia c. meridionalis
As with Parrot and Scottish Crossbills all of the above are fairly sedentary forms associated with hard-coned
Pinus species. The following are more associated with the softer cones of spruce and larch:
- Altai Crossbill, Loxia c. altaiensis
- Tien Shan Crossbill, Loxia c. tianschanica
- Himalayan Crossbill, Loxia c. himalayensis
- Japanese Crossbill, Loxia c. japonica
North American Red Crossbill subspecies list based on biometrics:
- Newfoundland Crossbill, Loxia c. percna Possibly extinct
- Lesser Crossbill, Loxia c. minor
- Sitka Crossbill, Loxia c. sitkensis
- Loxia c. neogaea
- Rocky Mountain Crossbill, Loxia c. benti
- Sierra Crossbill, Loxia c. grinnelli
- Bendire Crossbill, Loxia c. bendirei
- Mexican Crossbill, Loxia c. stricklandi
- Central American Crossbill, Loxia c. mesamericana
- South Hills Crossbill, Loxia c. ?
Jeff Groth's classification of North American Red Crossbill forms based on call-types:
- Type 1, corresponds with Loxia c. neogaea
- Recorded on Tsuga species, Picea glauca, Pinus strobus
- Type 2, corresponds with Loxia c. benti/grinnelli/bendirei
- Recorded on Pinus ponderosa scopulorum in the west and in various Pinus species in the east
- Type 3, corresponds with Loxia c. sitkensis and Loxia c. minor
- Type 4, corresponds with Loxia c. neogaea
- Type 5, corresponds with Loxia c. benti/grinnelli/bendirei
- Type 6, corresponds with Loxia c. stricklandi
- Uses Pine species in Section Trifoliae
- Type 7, corresponds with Loxia c. benti/grinnelli/bendirei
- In terms of diet this type is possibly a generalist
- Type 8, corresponds with Loxia c. percna
- Type 9, corresponds with South Hills Crossbill
Summers' list of European Common Crossbill forms (with Parrot & Scottish) based on Flight/Excitement calls:
- 1A, corresponds with "British" Crossbill
- 2B, corresponds with "Wandering" Crossbill
- 2D, corresponds with Parrot Crossbill Loxia pytyopsittacus
- 3C, corresponds with Scottish Crossbill Loxia scotica
- 3D, corresponds with Balearic Crossbill
- 3E, corresponds with North African Crossbill
- 4E, corresponds with "Glip" Crossbill
- 5D, corresponds with Cyprus Crossbill
"The Sound Approach's" classification of European Common Crossbill types based on call-types:
- "Wandering" Crossbill (Type A - flight call "Keep")
- "Bohemian" Crossbill (Type B - flight call "Weet")
- "Glip" Crossbill (Type C - flight call "Glip")
- "Phantom" Crossbill (Type D - flight call "Jip")
- "British" Crossbill (Type E - flight call "Chip")
- "Scarce" Crossbill (Type F - flight call "Trip")
- "Parakeet" Crossbill (Type X - flight call "Cheep")
References
External links
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Further reading
Book
Adkisson, C. S. 1996. Red Crossbill (Loxia curvirostra). In The Birds of North America, No. 256 (A. Poole and F. Gill, eds.).
The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists’ Union, Washington, D.C.
Thesis
- Benkman CW. Ph.D. (1985). THE FORAGING ECOLOGY OF CROSSBILLS IN EASTERN NORTH AMERICA (AVES, BREEDING BEHAVIOR,
MORPHOLOGY, CONIFERS). State University of New York at Albany, United States -- New York.
- Coombs-Hahn TP. Ph.D. (1993). Integration of environmental cues to time reproduction in an opportunistic breeder, the red
crossbill (Loxia curvirostra). University of Washington, United States -- Washington.
- Groth JG. Ph.D. (1990). Cryptic species of nomadic birds in the red crossbill (Loxia curvirostra) complex of North
America. University of California, Berkeley, United States -- California.
- Simard JH. M.Sc. (2001). Habitat selection, ecological energetics, and the effects of changes in white pine forests on
breeding red crossbills (Loxia curvirostra ) in Algonquin Provincial Park, Ontario. McGill University (Canada), Canada.
- Smith JW. Ph.D. (2005). The role of coevolution in promoting ecological speciation in red crossbills (Loxia curvirostra
complex). New Mexico State University, United States -- New Mexico.
- Wren LS. M.Sc. (2001). Continental and regional distribution and abundance patterns of boreal cardueline finches:
Influences of conifer seed availability. Memorial University of Newfoundland (Canada), Canada.
Articles
- Alonso D, Arizaga J, Miranda R & Campos F. (2003). Comparative biometrics of common crossbills (Loxia curvirostra) on
the Iberian Peninsula and the Bealearic Islands. Vogelwarte. vol 42, no 1-2. p. 116-117.
- Alonso D, Arizaga J, Miranda R & Hernandez MA. (2006). Morphological diversification of common crossbill Loxia
curvirostra populations within Iberia and the Balearics. Ardea. vol 94, no 1. p. 99-107.
- Arnaiz-Villena A, Guillen J, Ruiz-de-Valle V, Lowy E, Zamora J, Varela P, Stefani D & Allende LM. (2001).
Phylogeography of crossbills, bullfinches, grosbeaks, and rosefinches. Cellular and Molecular Life Sciences. vol
58, no 8. p. 1159-1166.
- Barboza PS & Jorde DG. (2002). Intermittent fasting during winter and spring affects body composition and reproduction
of a migratory duck. Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology. vol 172,
no 5. p. 419-434.
- Benkman CW. (1987). Food Profitability and the Foraging Ecology of Crossbills. Ecological Monographs. vol 57,
no 3. p. 251-267.
- Benkman CW. (1988). Flock Size Food Dispersion and the Feeding Behavior of Crossbills. Behavioral Ecology &
Sociobiology. vol 23, no 3. p. 167-176.
- Benkman CW. (1988). On the Advantages of Crossed Mandibles an Experimental Approach. Ibis. vol 130, no 2. p.
288-293.
- Benkman CW. (1993). ADAPTATION TO SINGLE RESOURCES AND THE EVOLUTION OF CROSSBILL (LOXIA) DIVERSITY. Ecological
Monographs. vol 63, no 3. p. 305-325.
- Benkman CW. (1993). The evolution, ecology, and decline of the red crossbill of Newfoundland. American Birds. vol
47, no 2. p. 225-229.
- Benkman CW. (1999). The selection mosaic and diversifying coevolution between crossbills and lodgepole pine. American
Naturalist. vol 153, p. S75-S91.
- Benkman CW. (2003). Divergent selection drives the adaptive radiation of crossbills. Evolution. vol 57, no 5.
p. 1176-1181.
- Benkman CW, Colquitt JS, Gould WR, Fetz T, Keenan PC & Santisteban L. (2005). Can selection by an ectoparasite drive a
population of red crossbills from its adaptive peak?. Evolution. vol 59, no 9. p. 2025-2032.
- Benkman CW, Holimon WC & Smith JW. (2001). The influence of a competitor on the geographic mosaic of coevolution
between crossbills and lodgepole pine. Evolution. vol 55, no 2. p. 282-294.
- Benkman CW & Lindholm AK. (1991). THE ADVANTAGES AND EVOLUTION OF A MORPHOLOGICAL NOVELTY. Nature. vol 349,
no 6309. p. 519-520.
- Benkman CW & Miller RE. (1996). Morphological evolution in response to fluctuating selection. Evolution. vol
50, no 6. p. 2499-2504.
- Benkman CW, Parchman TL, Favis A & Siepielski AM. (2003). Reciprocal selection causes a coevolutionary arms race
between crossbills and lodgepole pine. American Naturalist. vol 162, no 2. p. 182-194.
- Brauning DW, Brittingham MC, Gross DA, Leberman RC, Master TL & Mulvihill RS. (1994). Pennsylvania breeding birds of
special concern: A listing rational and status update. Journal of the Pennsylvania Academy of Science. vol 68, no 1.
p. 3-28.
- Brazier FH. (1996). A second breeding record of Red Crossbill in Regina. Blue Jay. vol 54, no 1.
- Clark WH. (1981). Highway Mortality of the Red Crossbill Loxia-Curvirostra. Journal of the Idaho Academy of Science.
vol 17, no 1. p. 1-2.
- Clouet M. (2000). The breeding biology of the Common Crossbill Loxia Curvirostra in the Central Pyrenees. Bird Study.
vol 47, p. 186-194.
- Clouet M. (2003). Bill size and breeding periode of pine forest crossbills. Revue D Ecologie-La Terre Et La Vie. vol
58, no 4. p. 419-433.
- Clouet M & Goar J-L. (2001). Note on the Philippine cross-bill Loxia curvirostra luzoniensis. Alauda. vol
69, no 2. p. 331-334.
- Coffey K, Benkman CW & Milligan BG. (1999). The adaptive significance of spines on pine cones. Ecology. vol
80, no 4. p. 1221-1229.
- Constantine M, & "The Sound Approach". (2006). The Sound Approach to Birding. A guide to understanding bird sound.
ISBN-10: 9081093312
- Cornelius JM, Breuner CW & Hahn TP. (2004). Effects of food reduction on stress reactivity in an irruptive nomad, the
red crossbill. Integrative and Comparative Biology. vol 44, no 6. p. 684-684.
- Dinsmore JJ. (1998). Iowa's avifauna: Recent changes and prospects for the future. Journal of the Iowa Academy of
Science. vol 105, no 3. p. 115-122.
- Edelaar P. (2003). Are there morphological differences between the vocal types of the common crossbill?. Vogelwarte.
vol 42, no 1-2. p. 115-116.
- Edelaar P. (2003). Is there assortative mating between the vocal types of the common crossbill?. Vogelwarte. vol
42, no 1-2.
- Edelaar P & Benkman CW. (2006). Replicated population divergence caused by localized coevolution? A test of three
hypotheses in the red crossbill-lodgepole pine system. Journal of Evolutionary Biology. vol 19, no 5. p.
1651-1659.
- Edelaar P, Phillips RE & Knops P. (2005). Sexually dimorphic body plumage in juvenile Crossbills. Wilson Bulletin.
vol 117, no 4. p. 390-393.
- Edelaar P & Terpstra K. (2004). The nominate subspecies of the Common Crossbill Loxia c. curvirostra polytypic? I.
Morphological differences among years at a single site. Ardea. vol 92, no 1. p. 93-102.
- Förschler MI, Förschler L & Dorka U. (2006). Population fluctuations of siskins Carduelis spinus, common crossbills
Loxia curvirostra, and citril finches Carduelis citrinella in relationship to flowering intensity of spruce Picea abies.
Ornis Fennica. vol 83, no 2. p. 91-96. http://www.birdlife.fi/julkaisut/of/pdf/vol83-2/6F%F6rschler2524.pdf
- Frost MP. (1985). Citril Finches Serinus-Citrinella and Crossbills Loxia-Curvirostra Eating Minerals. British Birds.
vol 78, no 1.
- Genard M & Lescourret F. (1987). The Common Crossbill Loxia-Curvirostra in the Pyrenees France Some Observations on
Its Habitats and on Its Relations with Conifer Seeds. Bird Study. vol 34, no 1. p. 52-63.
- Gilbert FF & Allwine R. (1991). Spring Bird Communities in the Oregon Cascade Range USA. U S Forest Service
General Technical Report PNW. vol 285, p. 145-159.
- Groth JG. (1988). Resolution of Cryptic Species in Appalachian Red Crossbills. Condor. vol 90, no 4. p.
745-760.
- Groth JG. (1993). Call matching and positive assortative mating in Red Crossbills. The Auk. vol 110, no 2. p.
398.
- Hahn T. (1990). PHYSIOLOGICAL CORRELATES OF OPPORTUNISTIC BREEDING IN THE RED CROSSBILL. American Zoologist. vol
30, no 4. p. A53-A53.
- Hahn T. (1992). Seasonal components of reproductive function in a reproductive opportunist, the red crossbill, Loxia
curvirostra. American Zoologist. vol 32, no 5.
- Hahn TP. (1994). Crossbill diversity -- Evolutionary Differentiation in Morphology, Vocalizations, and Allozymes Among
Nomadic Sibling Species in the North American Red Crossbill (Loxia curvirostra) Complex by J. G. Groth. The Condor. vol
96, no 3. p. 835.
- Hahn TP. (1995). Integration of Photoperiodic and Food Cues to Time Changes in Reproductive Physiology by an Opportunistic
Breeder, the Red Crossbill, Loxia curvirostra (Aves: Carduelinae). Journal of Experimental Zoology. vol 272, no 3. p.
213-226.
- Hahn TP. (1996). Habitat preferences and biogeography of cryptic species in the North American red crossbill complex
(Loxia curvirostra; Aves: Carduelinae). American Zoologist. vol 36, no 5.
- Hahn TP. (1998). Reproductive seasonality in an opportunistic breeder, the red crossbill, Loxia curvirostra. Ecology.
vol 79, no 7. p. 2365-2375.
- Hau M. (2001). Timing of breeding in variable environments: Tropical birds as model systems. Hormones and Behavior.
vol 40, no 2. p. 281-290.
- Hau M, Wikelski M & Wingfield JC. (2000). Visual and nutritional food cues fine-tune timing of reproduction in a
neotropical rainforest bird. Journal of Experimental Zoology. vol 286, no 5. p. 494-504.
- Herbers JR, Serrouya R & Maxcy KA. (2004). Effects of elevation and forest cover on winter birds in mature forest
ecosystems of southern British Columbia. Canadian Journal of Zoology-Revue Canadienne De Zoologie. vol 82, no 11. p.
1720-1730.
- Hernandez M, Alonso D, Arizaga J, Amezcoa A, Alda F, Murua A, Schroder P-C & Campos F. (2003). Comparative molecular
study of populations of common crossbill (Loxia curvirostra) on the Iberian Peninsula and the Balearic Islands. Vogelwarte.
vol 42, no 1-2.
- Hill GE & Benkman CW. (1995). Exceptional response by female red crossbills to dietary carotenoid supplementation.
The Wilson Bulletin. vol 107, no 3. p. 555.
- Hogstad O. (1990). Winter Territoriality and the Advantages of Social Foraging in the Treecreeper Certhia-Familiaris.
Fauna Norvegica Series C Cinclus. vol 13, no 2. p. 57-64.
- Holimon WC, Benkman CW & Willson MF. (1998). The importance of mature conifers to red crossbills in southeast
Alaska. Forest Ecology and Management. vol 102, no 2-3. p. 167-172.
- Hubalek Z. (1984). Avifauna of the Island of Brac Yugoslavia. Larus. vol 37, p. 167-174.
- Iovchenko NP. (2003). Relationship of moult and breeding in the Tien Shan subspecies of the common crossbill Loxia
curvirostra tianshanica. Vogelwarte. vol 42, no 1-2.
- Jacobs JD & Wingfield JC. (2000). Endocrine control of life-cycle stages: A constraint on response to the
environment?. Condor. vol 102, no 1. p. 35-51.
- Jardine DC. (1994). Brood patch on a Common Crossbill Loxia curvirostra still in juvenile plumage. Bird Study. vol
41, no 2. p. 155-156.
- Jardine DC. (1994). Observations on the occurrence of red-orange female common crossbills Loxia curvirostra. Ringing
& Migration. vol 15, no 2. p. 98-100.
- Jardine DC. (2000). Common Crossbill eating adelgids. Scottish Birds. vol 21, no 1. p. 52-53.
- Johnson NK, Marten JA & Ralph CJ. (1989). Genetic Evidence for the Origin and Relationships of Hawaiian Honeycreepers
Aves Fringillidae. Condor. vol 91, no 2. p. 379-396.
- Kelsey R & Hahn TP. (2004). Distribution and abundance of a nomadic seed specialist, the red crossbill, in the western
United States. Integrative and Comparative Biology. vol 44, no 6. p. 712-712.
- Knox AG. (1990). Identification of Crossbill and Scottish Crossbill. British Birds. vol 83, no 3. p.
89-94.
- Knox AG. (1990). THE SYMPATRIC BREEDING OF COMMON AND SCOTTISH CROSSBILLS LOXIA-CURVIROSTRA AND LOXIA-SCOTICA AND THE
EVOLUTION OF CROSSBILLS. Ibis. vol 132, no 3. p. 454-466.
- Koenig WD. (2001). Synchrony and periodicity of eruptions by boreal birds. Condor. vol 103, no 4. p.
725-735.
- Koenig WD & Knops JMH. (2001). Seed-crop size and eruptions of North American boreal seed-eating birds. Journal of
Animal Ecology. vol 70, no 4. p. 609-620.
- Lewartowski Z & Wolk K. (1983). Breeding Avi Fauna of a Moss Spruce Forest and Related Habitats in the Bialowieza
Primeval Forest Poland. Acta Ornithologica. vol 19, no 1-6. p. 97-112.
- MacDougall-Shackleton SA, Deviche PJ, Crain RD, Ball GF & Hahn TP. (2001). Seasonal changes in brain GnRH
immunoreactivity and song-control nuclei volumes in an opportunistically breeding songbird. Brain Behavior and Evolution. vol
58, no 1. p. 38-48.
- MacDougall-Shackleton SA, Katti M & Hahn TP. (2006). Tests of absolute photorefractoriness in four species of
cardueline finch that differ in reproductive schedule. Journal of Experimental Biology. vol 209, no 19. p.
3786-3794.
- Manuwal DA & Huff MH. (1987). Spring and Winter Bird Populations in a Douglas-Fir Forest Sere. Journal of Wildlife
Management. vol 51, no 3. p. 586-595.
- Marquiss M. (1980). Some Biometrics of Common Crossbills Loxia-Curvirostra from Ae Forest Dumfriesshire England Uk.
Ringing & Migration. vol 3, no 1. p. 35-36.
- Marquiss M & Rae R. (1994). Seasonal trends in abundance, diet and breeding of common crossbills (Loxia curvirostra)
in an area of mixed species conifer plantation following the 1990 crossbill 'Irruption'. Forestry. vol 67, no 1. p.
31-47.
- Marten JA & Johnson NK. (1986). Genetic Relationships of North American Cardueline Finches. Condor. vol 88,
no 4. p. 409-420.
- Massa B. (1987). Variations in Mediterranean Crossbills Loxia-Curvirostra. Bulletin of the British Ornithologists'
Club. vol 107, no 3. p. 118-128.
- McGhie HA & Summers RW. (2000). Egg sizes of crossbills in Scotland. Scottish Birds. vol 21, no 2. p.
85-87.
- Mezquida ET & Benkman CW. (2005). The geographic selection mosaic for squirrels, crossbills and Aleppo pine.
Journal of Evolutionary Biology. vol 18, no 2. p. 348-357.
- Newton I. (2006). Movement patterns of common crossbills Loxia curvirostra in europe. Ibis. vol 148, no 4. p.
782-788.
- Noskov GA, Iovchenko NP & Smirnov YN. (2003). Sexual activity, moult and movements in the annual cycle in the common
crossbill Loxia curvirostra. Vogelwarte. vol 42, no 1-2. p. 114-115.
- Parchman TL & Benkman CW. (2002). Diversifying coevolution between crossbills and black spruce on Newfoundland.
Evolution. vol 56, no 8. p. 1663-1672.
- Parchman TL, Benkman CW & Britch SC. (2006). Patterns of genetic variation in the adaptive radiation of New World
crossbills (Aves : Loxia). Molecular Ecology. vol 15, no 7. p. 1873-1887.
- Patterson IJ, Ollason JG & Doyle P. (1995). Bird populations in upland spruce plantations in northern Britain.
Forest Ecology and Management. vol 79, no 1-2. p. 107-131.
- Payne RB. (1987). Populations and Type Specimens of a Nomadic Bird Comments on the North American Crossbills Loxia-Pusilla
Gloger 1834 and Crucirostra-Minor Brehm 1845. Occasional Papers of the Museum of Zoology University of Michigan. vol
714, p. 1-37.
- Pereyra ME, MacDougall-Shackleton SA, Sharbaugh SM, Morton ML, Katti M & Hahn TP. (2001). Relationships between
photorefrac-toriness and reproductive flexibility in cardueline finches. American Zoologist. vol 41, no 6.
- Pereyra ME, Sharbaugh SM & Hahn TP. (2005). Interspecific variation in photo-induced GnRH plasticity among nomadic
cardueline finches. Brain Behavior and Evolution. vol 66, no 1. p. 35-49.
- Peterson AT. (1996). Reviews -- Evolutionary Differentiation in Morphology, Vocalizations, and Allozymes Among Nomadic
Sibling Species in the North American Red Crossbill (Loxia curvirostra) Complex by Jeffrey G. Groth. The Auk. vol 113,
no 2. p. 519.
- Petty SJ, Patterson IJ, Anderson DIK, Little B & Davison M. (1995). Numbers, breeding performance, and diet of the
sparrowhawk Accipiter nisus and merlin Falco columbarius in relation to cone crops and seed-eating finches. Forest Ecology
and Management. vol 79, no 1-2. p. 133-146.
- Pflumm W. (1984). SEXUAL DIFFERENCES IN FEEDING RATES OF COMMON CROSSBILLS (LOXIA-CURVIROSTRA). Journal Fur
Ornithologie. vol 125, no 4. p. 481-482.
- Phillips AR. (1977). SEX AND AGE-DETERMINATION OF RED CROSSBILLS (LOXIA-CURVIROSTRA). Bird-Banding. vol 48, no
2. p. 110-117.
- Piertney SB, Summers R & Marquiss M. (2001). Microsatellite and mitochondrial DNA homogeneity among phenotypically
diverse crossbill taxa in the UK. Proceedings of the Royal Society of London Series B-Biological Sciences. vol 268, no
1475. p. 1511-1517.
- Questiau S, Gielly L, Clouet M & Taberlet P. (1999). Phylogeographical evidence of gene flow among Common Crossbill
(Loxia curvirostra, Aves, Fringillidae) populations at the continental level. Heredity. vol 83, p. 196-205.
- Rising JD. (1995). Ornithological literature -- Evolutionary Differentiation in Morphology, Vocalizations, and Allozymes
among Nomadic Sibling Species in the North American Red Crossbill (Loxia curvirostra) Complex by Jeffrey G. Groth. The Wilson
Bulletin. vol 107, no 2. p. 389.
- Senar JC, Borras A, Cabrera T & Cabrera J. (1993). TESTING FOR THE RELATIONSHIP BETWEEN CONIFEROUS CROP STABILITY AND
COMMON CROSSBILL RESIDENCE. Journal of Field Ornithology. vol 64, no 4. p. 464-469.
- Senar JC, Conroy MJ, Borras A, Cabrera T & Cabrera J. (2003). Population dynamics of a resident common crossbill
population. Vogelwarte. vol 42, no 1-2.
- Shaw D & Flick C. (1999). Are resident songbirds stratified within the canopy of a coniferous old-growth forest?.
Selbyana. p. 28, 1999.
- Siepielski AM & Benkman CW. (2004). Interactions among moths, crossbills, squirrels, and lodgepole pine in a
geographic selection mosaic. Evolution. vol 58, no 1. p. 95-101.
- Siepielski AM & Benkman CW. (2005). A role for habitat area in the geographic mosaic of coevolution between red
crossbills and lodgepole pine. Journal of Evolutionary Biology. vol 18, no 4. p. 1042-1049.
- Smith JW, Benkman CW & Coffey K. (1999). The use and misuse of public information by foraging red crossbills.
Behavioral Ecology. vol 10, no 1. p. 54-62.
- Stradi R, Celentano G & Nava D. (1995). Separation and identification of carotenoids in bird's plumage by
high-performance liquid chromatography-diode-array detection. Journal of Chromatography B Biomedical Applications. vol
670, no 2. p. 337-348.
- Stradi R, Pini E & Celentano G. (2001). Carotenoids in bird plumage: the complement of red pigments in the plumage of
wild and captive bullfinch (Pyrrhula pyrrhula). Comparative Biochemistry and Physiology B-Biochemistry & Molecular
Biology. vol 128, no 3. p. 529-535.
- Stradi R, Rossi E, Celentano G & Bellardi B. (1996). Carotenoids in bird plumage: The pattern in three Loxia species
and in Pinicola enucleator. Comparative Biochemistry and Physiology B-Biochemistry & Molecular Biology. vol 113,
no 2. p. 427-432.
- Summers RW & Jardine DC. (2005). Vocal similarities between Mediterranean and north European pine Crossbills Loxia
spp. Ardeola. vol 52, no 2. p. 269-278.
- Summers RW, Jardine DC, Marquiss M & Proctor R. (1996). The biometrics of invading common crossbills Loxia curvirostra
in Britain during 1990-1991. Ringing & Migration. vol 17, no 1. p. 1-10.
- Summers RW, Jardine DC, Marquiss M & Rae R. (2002). The distribution and habitats of crossbills Loxia spp. in Britain,
with special reference to the Scottish Crossbill Loxia scotica. Ibis. vol 144, no 3. p. 393-410.
- Susic G. (1981). Red Crossbill Loxia-Curvirostra Feeding on Mortar in a Wall. Larus. vol 35, p. 197-200.
- Tallman DA & Zusi RL. (1984). A Hybrid Red Crossbill Pine Siskin Loxia-Curvirostra X Carduelis-Pinus and Speculations
on the Evolution of Loxia. Auk. vol 101, no 1. p. 155-158.
- Tanttu JT, Turunen J, Selin A & Ojanen M. (2006). Automatic feature extraction and classification of crossbill (Loxia
spp.) flight calls. Bioacoustics-the International Journal of Animal Sound and Its Recording. vol 15, no 3. p.
251-269.
- Thibault JC, Prodon R, Villard P & Seguin JF. (2006). Habitat requirements and foraging behaviour of the Corsican
nuthatch Sitta whiteheadi. Journal of Avian Biology. vol 37, no 5. p. 477-486.
- Tomek T. (1984). Materials to the Breeding Avifauna of North Korea. Acta Zoologica Cracoviensia. vol 27, no
1-11. p. 19-46.
- Tomialojc L. (1995). The birds of the Bialowieza Forest. Additional data and summary. Acta Zoologica Cracoviensia. vol
38, no 3. p. 363-397.
- Valkiunas G, Liutkevicius G & Iezhova TA. (2002). Complete development of three species of Haemoproteus (Haemosporida,
Haemoproteidae) in the biting midge Culicoides impunctatus (Diptera, Ceratopogonidae). Journal of Parasitology. vol
88, no 5. p. 864-868.
- Virkkala R. (2004). Bird species dynamics in a managed southern boreal forest in Finland. Forest Ecology and
Management. vol 195, no 1-2. p. 151-163.
- Wikelski M, Hau M, Robinson WD & Wingfield JC. (2003). Reproductive seasonality of seven neotropical passerine
species. Condor. vol 105, no 4. p. 683-695.
- Wikelski M, Hau M & Wingfield JC. (2000). Seasonality of reproduction in a neotropical rain forest bird. Ecology.
vol 81, no 9. p. 2458-2472.
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