Pyrrhuloxia diet

[DAVID A LEATHERMAN]

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%.

[Carol Blackard]

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

Carol Blackard

carolblackard.com

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



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[Jeff Percell]

Here is my checklist from yesterday afternoon. There is a photo of a House Finch who was in the same tree (someone had mentioned it was a hackberry though I'm terrible at tree ID, only slightly better at birds :D). As seen in the photo, the finch was at the top of the tree, eating the organic material of the tree - not sure if it is new budding material or old material from last year that is being pushed out. The Pyrrhuloxia stayed in the same spot the 20 minutes I was there, visible, but back in the branches a bit. It appeared to be resting, closing its eyes briefly off and on. It did one good stretch which is also captured in the photos.

You can also see from the photos that the Canada Goose has perhaps a more diverse diet.

https://ebird.org/checklist/S102603933

Thanks,

Jeff Percell

Erie, CO

[DAVID A LEATHERMAN]

At least four people have sent me pics or descriptions of house finches at or near the pyrrhuloxia yard eating tree parts and have said the pyrrhuloxia was associating with the finches for a lengthy period of time, maybe doing the same thing.  The "tree parts" are buds.  Trees have two primary types of buds: flower buds and leaf buds.  At this time of year the flower buds, which are first to open for most types of trees, swell.  As such they are nutritional sinks and a valuable source of bird food, especially for finches, cardinals and the like.  The tree shown in the pics I've received looks like Siberian elm, a tree that has been flowering earlier and earlier in my experience.  In recent years I have seen a few elm flowers in late February, with March being the peak.  It would be cool if somebody could document the pyrrhuloxia eating Siberian elm flower buds.  Birds actively consuming large numbers of buds, which is a messy operation, often show considerable "debris" on their beaks.  Maybe one of you has a photo of the pyrrhuloxia with a messy beak and it could be determined if the mess is from sunflower seed or tree buds.  A photo of the pyrrhuloxia actually putting its beak down to a twig with swollen dark brown buds would be better proof.

We all know animals are opportunists.  Studying fox squirrels over the years, I have long thought one could pretty accurately predict the order in which our urban trees flower and/or leaf out by noting the tree species when one sees squirrels chowing down on buds and dropping the worked over twigs.  The squirrels favoring one kind of tree this week will most likely be in a different type of tree next week.  Keep track of the sequence and I think it would be a good match to the flowering/leafing sequence for that same set of trees weeks hence.  Somehow, probably related to smell in the case of squirrels, they know where to get the biggest bang for the bite.  The pattern doesn't seem quite as clearcut for birds.  My thought would be that birds are going by visual clues (i.e., watching for swelling which indicates a recent or on-going investment in the growing points by the plant), and that visual assessment might not be as precise as the aromatic acuity possessed by squirrels.

Memberships in the CSFTEA (Colorado Society For The Easily Amused) are free.  Join today.

Dave Leatherman

Fort Collins

[Carol Blackard]

Lateral but still birdy shift here: I’ve been watching bushtits picking off and downing buds from our Flowering Quince bushes in March for years, sometimes chickadees. At first I thought they might be going for insect larvae, but I now think it’s the flower buds.

Carol Blackard

carolblackard.com

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On Feb 14, 2022, at 9:16 AM, DAVID A LEATHERMAN <daleat...@msn.com> wrote:



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[Jennifer Powell]

We have some shrubby wild plums that grow around our yard and every spring I see birds, usually house finches, methodically going up and down the stems eating early flower buds one after another.

Jennifer Powell

Jeffco, near Standley Lake

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[Kelly Ambler]

Interesting observations, David.

I have noticed that hackberry trees are some of the earliest native trees/shrubs to bloom in our area. It would be interesting to verify the tree identity. 

Kelly Ambler

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[Carol Blackard]

It’s still a couple of weeks early for the Quince to be really budding up. When I see the bushtits getting interested in it in a couple of weeks or so, I’ll check carefully for aphids and scaly stuff. However, last year I was able to see actual petals in their beaks on a few occasions, so I did decide they were after flower buds.

Carol Blackard

carolblackard.com

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On Feb 14, 2022, at 8:29 PM, Jennifer Powell <jn...@well.com> wrote:



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[ROBERT SANTANGELO]

Yesterday (2/14) I gifted the homeowner with about 10 lbs of jumbo white-striped sunflower seed that I was still hoarding from the grosbeaks that visited my yard last May and are expected to show up again this year. Will be curious to see if it takes a keener interest in those opposed to the black-oil seeds being offered presently.