Similarly, pinyon jays (Gymnorhinus cyanocephalus
), which are highly social corvids, determine their own relative rank within the hierarchy by combining information from within-group direct dominance encounters (competing with another individual for access to a peanut) with information gained from subsequently observing encounters between other birds (Paz-y-Mino et al., 2004).
One is Clark's nutcracker, which stores more food than any of the others; the second is the pinyon jay (Gymnorhinus cyanocephalus
), which stores less food than Clark's nutcracker, but more than the third species, the scrub jay (Aphelocoma coerulescens); if degree of dependence on stored food is associated with an enhanced spatial memory, then on spatial tasks the more dependent species should outperform the less dependent.
macularia in the order Ciconiiformes; and Aphelocoma coerulescens, Catharus mustelinus, Dendroica discolor, Gymnorhinus cyanocephalus
, Melospiza melodia, and Parus major in the order Passeriformes.
Flocking and annual cycle of the pinon jay, Gymnorhinus cyanocephalus
. Condor 73: 287-302.
Females with more conspicuous plumage than other females of the same species have been shown to be more aggressive in some species: pinyon jays (Gymnorhinus cyanocephalus
, Johnson 1988), some hummingbirds (Bleiwess 1985, 1992), and in capuchinbirds (Perissocephalus tricolor, Trail 1990).
Crossbills appear to be similar to Pinyon Jays (Gymnorhinus cyanocephalus
), which can nest opportunistically in late summer if green cones of pinyon pine (Pinus monophylla) are abundant (Ligon 1974, 1978), but which appear to be refractory to both photoperiod and cones by about the end of September (Ligon 1978).