Re: [cobirds] Pyrrhuloxia diet

Thank you, David for the dietary information on the pyrrhuloxia. Interesting as always.

Carol Blackard

carolblackard.com

Sent from my iPhone

On Feb 13, 2022, at 9:29 PM, DAVID A LEATHERMAN <daleatherman@msn.com> wrote:



Carol, Linda and anyone else interested, I have cut and pasted below the section on pyrrhuloxia diet from the "Birds of the World" account by Robert Tweit and Christopher Thompson.

Photos I have seen of the current Colorado bird show it at a black oil sunflower feeder.  The fruits of hackberry are technically called drupes.  At this time of year the reddish pulp of each fruit is mostly eroded/withered and what remains is a hard pit dangling from a thin stalk (or resting on the ground).  I see more birds eating the fresh fruits in late summer/autumn, probably for their pulp mostly, with the pits being excreted.  However, I have seen a few birds like juncos and house finches eating the fruits of hackberry in winter when they must be crunching the rock-hard seeds.  Pyrrhuloxias certainly appear to have the beak to handle hard seeds, so perhaps the association with hackberry is more than just positioning for a feeder visit.  Verification welcome.

Dave Leatherman

Fort Collins

Diet

Major Food Items

In Texas, wide variety of seeds, including bristle grass (Setaria spp.), doveweed (Croton texensis), sandbur (Cenchrus spp.), panicum (Panicum spp.), sorghum, and pigweed (Chenopodium album), and fruits of cactus (Opuntia spp.) and nightshade (Solanum spp.), as well as grasshoppers, caterpillars (Lepidoptera), beetles (Coleoptera), stinkbugs (Pentatomidae), and cicadas (Cicadidae). McAtee (McAtee 1908a) suggested that Pyrrhuloxia prefers grasshoppers to caterpillars to beetles and eats much less fruit than Northern Cardinal does.

In s. Arizona, prefers sunflower (Helianthus spp.) seeds and "peanut butter suet" at feeders, although also eats other seeds and household scraps (Anderson 1968).

Quantitative Analysis

From McAtee 1908a . In Aug and Sep, stomachs collected in Texas contained 71.2% vegetable matter and 28.8% animal matter. Most of the vegetable matter (53.1% of total) was "grass seeds," primarily yellow foxtail (Chaetecholoa glauca) and bur grass (Cenchrus tribuloides), which provide 43.6% of total food. Other weed seeds included crabgrass (Syntherisma spp.), joint grass (Paspalum spp.), and wire grass (Eleusine indica). Seeds of a spurge (Croton sp.) made up 9.8% of diet. Of the remaining seeds, only sorghum made measurable contribution (2.0%). Animal matter made up of beetles (4.7%) (mainly weevils [3.4%], including cotton boll weevil [Anthononus grandis]), caterpillars (10.3%, including cotton worm [Alabama argillacea]), and cotton cutworm (Prodenia ornithogalli). Grasshoppers made up 11.5% and true bugs (Hemiptera) 1.5%.

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