[cobirds] Pyrrhuloxia diet

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.

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Dave Leatherman

Fort Collins