The Two-barred Crossbill (Loxia leucoptera), known as the White-winged Crossbill in
North America, is a small passerine bird in the finch family Fringillidae.
This bird breeds in the coniferous forests of Alaska,
Canada, northernmost USA and across
Asia extending into northeast Europe. It nests in conifers, laying
3-5 eggs.
This crossbill is mainly resident, but will irregularly erupt south if its food source fails. The American race seems to wander more frequently than the Eurasian
subspecies. This species will form flocks outside the breeding season, often mixed with other crossbills. It is a rare visitor to
western Europe, usually arriving with an eruption of Common 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, and the
unusual bill shape is an adaptation to assist the extraction of the seeds from the cone. Two-barred Crossbill has a strong
preference for larch (Larix), in Eurasia using Siberian larch (Larix sibirica) and
Dahurian larch (L. gmelinii), and in North America Tamarack larch (L. laricina). It will also take Rowan Sorbus berries, and in North America, also Eastern Hemlock (Tsuga
canadensis) and White spruce (Picea glauca) cones.
Adult males tend to be red or pinkish in colour, and females green or yellow, but there is much variation. Two-barred is
easier to identify than other crossbills, especially in North America, where only Red Crossbill and this species occur, but some
care is still needed.
Within its Eurasian range, this species is smaller-headed and smaller-billed than
Parrot Crossbill and Scottish Crossbill, so
the main confusion species both there and in North America is Common or Red Crossbill.
The main plumage distinction from Common Crossbills is the white wingbars which give this species its English and scientific names. There are also white tips to the tertials. The adult male is also a
somewhat brighter (pinker) red than other male crossbills. Some Common Crossbills occasionally show weak white wingbars, so care
is needed with the correct identification of this species. The chip call is weaker and higher than that of Common
Crossbill.
Another crossbill on Hispaniola was previously treated as a subspecies, Loxia
leucoptera megaplaga, but is now treated as a distinct species, Hispaniolan
Crossbill, Loxia megaplaga. It is associated with the Hispaniolan pine Pinus occidentalis, and differs from
Two-barred Crossbill in darker plumage and a stouter bill.
Exceptional southern vagrancy in America?
On 11 January 2007 a White-winged Crossbill was found dead
in the parking lot at Long Pine Key Picnic Area in Everglades National Park, Florida. Current speculation is that
the bird may have been hit by a recreational vehicle that was on its way south from
the bird's natural range, and simply fell off after arrival in Florida. It is hoped that during the preparation of the
specimen an examination of the bird's stomach contents could help prove or disprove this
hypothesis. Alternatively, it is possible that the bird could have originated from the
Hispaniolan population. [1]
Photo image links
References
- ^ Postings to Tropical Audubon Society
Miami Bird Board, 12 January 2007. link to discovery message
Further reading
Book
- Benkman C. W. 1992. White-winged Crossbill (Loxia leucoptera). In The Birds of North America, No. 27. (A.
Poole, P. Stettenheim, and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The American
Ornithologists’ Union.
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.
Articles
- Benkman CW. (1987). Crossbill Foraging Behavior Bill Structure and Patterns of Food Profitability. Wilson Bulletin.
vol 99, no 3. p. 351-368.
- Benkman CW. (1987). Food Profitability and the Foraging Ecology of Crossbills. Ecological Monographs. vol 57,
no 3. p. 251-267.
- Benkman CW. (1989). Intake Rate Maximization and the Foraging Behavior of Crossbills. Ornis Scandinavica. vol
20, no 1. p. 65-68.
- Benkman CW. (1990). Intake Rates and the Timing of Crossbill Reproduction. Auk. vol 107, no 2. p. 376-386.
- Benkman CW. (1994). Comments on the ecology and status of the hispaniolan crossbill (Loxia leucoptera megaplaga), with
recommendations for its conservation. Caribbean Journal of Science. vol 30, no 3-4. p. 250-254.
- Benkman CW. (1997). Feeding behavior, flock-size dynamics, and variation in sexual selection in crossbills. Auk. vol
114, no 2. p. 163-178.
- Coady G. (2001). First nest record of white-winged crossbill in the greater Toronto area. Ontario Birds. vol
19, no 3. p. 101-111.
- Deviche P. (1997). Seasonal reproductive pattern of white-winged Crossbills in interior Alaska. Journal of Field
Ornithology. vol 68, no 4. p. 613-621.
- Deviche P. (2000). Timing, pattern, and extent of first prebasic molt of White-winged Crossbills in Alaska. Journal of
Field Ornithology. vol 71, no 2. p. 217-226.
- Deviche P & Hahn TP. (1995). SEasonal reproductive pattern of interior Alaska white-winged crossbills (Loxia
leucoptera). American Association for the Advancement of Science, Arctic Division. p. Landscapes Human ecology, landscape
ecology, earth system science.
- Deviche P & Sharp PJ. (2001). Reproductive endocrinology of a free-living, opportunistically breeding passerine
(White-winged Crossbill, Loxia leucoptera). General and Comparative Endocrinology. vol 123, no 3. p. 268-279.
- Elmberg J. (1993). Song differences between North American and European White-winged Crossbills (Loxia leucoptera).
The Auk. vol 110, no 2. p. 385.
- Eykhler V & Vasyukova TT. (1981). A New Species of the Genus Docophorulus Mallophaga Philopteridae from the
White-Winged Crossbill Loxia-Leucoptera-Bifasciata. Entomological Review. vol 60, no 3. p. 99-101.
- Fischer S, Mauersberger G, Schielzeth H & Witt K. (1992). 1ST BREEDING RECORD OF 2-BARRED CROSSBILL (LOXIA-LEUCOPTERA)
IN CENTRAL-EUROPE. Journal Fur Ornithologie. vol 133, no 2. p. 197-202.
- Gallant D. (2004). White-winged crossbills obtain forage from river otter Feces. Wilson Bulletin. vol 116, no 2. p.
181-184.
- Gordon P, Morlan J & Roberson D. (1989). First Record of the White-Winged Crossbill in California USA. Western
Birds. vol 20, no 2. p. 81-88.
- Groth JG. (1992). Further Information on the Genetics of Bill Crossing in Crossbills. The Auk. vol 109, no 2.
p. 383.
- Groth JG. (1992). White-Winged Crossbill Breeding in Southern Colorado with Notes on Juveniles Calls. Western Birds.
vol 23, no 1. p. 35-38.
- Hahn TP, Pereyra ME & Sharbaugh SM. (2003). Effects of photoperiod on brain GnRH plasticity and peripheral
reproductive physiology in three species of cardueline finches. Society for Neuroscience Abstract Viewer & Itinerary
Planner. p. 611.
- Hahn TP, Pereyra ME, Sharbaugh SM & Bentley GE. (2004). Physiological responses to photoperiod in three cardueline
finch species. General and Comparative Endocrinology. vol 137, no 1. p. 99-108.
- Hahn TP, Wingfield JC, Mullen R & Deviche PJ. (1995). ENDOCRINE BASES OF SPATIAL AND TEMPORAL OPPORTUNISM IN
ARCTIC-BREEDING BIRDS. American Zoologist. vol 35, no 3. p. 259-273.
- Hobson KA & Bayne E. (2000). Breeding bird communities in boreal forest of western Canada: Consequences of "unmixing"
the mixedwoods. Condor. vol 102, no 4. p. 759-769.
- Kepler AK, Kepler CB & Dod A. (1975). FIRST NEST RECORD OF WHITE-WINGED CROSSBILL IN HISPANIOLA. Condor. vol
77, no 2. p. 220-221.
- 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.
- Latta SC, Sondreal ML & Brown CR. (2000). A hierarchical analysis of nesting and foraging habitat for the conservation
of the Hispaniolan White-winged crossbill (Loxia leucoptera megaplaga). Biological Conservation. vol 96, no 2. p.
139-150.
- Latta SC, Sondreal ML & Mejia DA. (2002). Breeding behavior of the endangered Hispaniolan Crossbill (Loxia
megaplaga). Ornitologia Neotropical. vol 13, no 3. p. 225-234.
- 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.
- McNair DB. (1990). First Modern Record of White-Winged Crossbill in Georgia USA a Commentary. Oriole. vol 53,
no 4. p. 49-50.
- Mundinger PC. (1979). Call Learning in the Carduelinae Ethological and Systematic Considerations. Systematic Zoology.
vol 28, no 3. p. 270-283.
- Nankinov DN, Ilkov PG & Stoychev KS. (1999). White-winged crossbill (Loxia leucoptera bifasciata C. L. Brehm, 1827) in
Bulgaria. Acta Zoologica Bulgarica. vol 51, no 1. p. 49-51.
- Oberle MW. (1986). First Modern Record of White-Winged Crossbill in Georgia USA. Oriole. vol 51, no 2-3. p.
25-27.
- Oberle MW & Hahn T. (1994). More on the White-winged crossbill in Georgia. Oriole. vol 59, no 1. p.
26-27.
- 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.
- 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.
- Pulliainen E. (2002). Chemical composition of the seed food of late-summer-breeding two-barred crossbills Loxia
leucoptera. Aquilo Ser Zoologica. vol 30, p. 79-81.
- Sealy SG, Sexton DA & Collins KM. (1980). Observations of a White-Winged Crossbill Loxia-Leucoptera Invasion of
Southeastern Manitoba Canada. Wilson Bulletin. vol 92, no 1. p. 114-116.
- Steinberg B & Tozer R. (2003). White-winged Crossbill predation by Blue Jay. Ontario Birds. vol 21, no 1.
p. 34-37.
- 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.
- West GC. (1974). ABNORMAL BILL OF A WHITE-WINGED CROSSBILL. Auk. vol 91, no 3. p. 624-626.
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