REFERRED MATERIAL Distal mandibular symphyses, DMNH 43343.
provenance Location 1349, Velvet Room, Mark's Sink.
DESCRIPTION This specimen is similar to Zonotrichia leucophrys but is too fragmentary for specific identification.
JUNCO HYEMALIS (LINNAEUS, 1758)
REFERRED MATERIAL Premaxilla, DMNH 30164; distal mandibular symphysis, DMNH 35754.
provenance 30164: Location 644, Velvet Room, grid 8/8A, level 2 (A); 35754: Location 1349, Velvet Room, Mark's Sink, level 19.
DESCRIPTION The ventral surface of the premaxilla in Junco and DMNH 30164 has more distinct concavities and a more distinct midline ridge compared to Zonotrichia and Melospiza. J. hyemalis occurs throughout Colorado today.
CALCARIUS LAPPONICUS (LINNAEUS, 1758)
REFERRED MATERIAL Three premaxillae, DMNH 35722, 41207, and 41220.
PROVENANCE 35722: Location 1349, Mark's Sink, level 16; 41207: Location 1349, Mark's Sink, level 19; 41220: Location 1349, Mark's Sink, level 22.
DESCRIPTION These specimens were also compared to Calcarius ornatus, C. pictus, and C. mccownii. In C. lapponicus and C. pictus, the premaxillae are slightly smaller and narrower at the base than in C. ornatus. C. mccownii is distinctly larger, with a longer and more robust bill, than C. ornatus, C. lapponicus, and C. pictus. Compared to C. pictus, C. lapponi-cus has a slightly longer and narrower bill. C. lapponicus occurs primarily in the eastern plains of Colorado during winter, but it also has been reported from mountain parks and valleys. It prefers grassland and prairie habitats.
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