I just got back from 11 days in the Lamar, CO (Prowers County) area visiting a friend and birding.
Birders look forward to May in CO because it is the peak of spring migration for many species of songbirds that winter in the neotropics and that either breed here or pass thru to breed north of us. I was struck this visit to southeastern CO by the use of the statewide native shrub golden currant (Ribes aureum) by many species of neotropical migrant birds. The reason was a food item they were finding in abundance, a tiny psyllid Dr. Whitney Cranshaw correctly determined as Cacopsylla ribisiae.
The overwhelming majority of psyllid individuals I saw on these native shrubs were wingless nymphs, but some of the feeding birds jumped up in the air in pursuit of what most likely were flying adults.
Nymph showing wing pads (actual length about 1/8th of an inch).
Adult psyllid (actual length about 3/16 of an inch).
Many of the nymphs displayed a bright white curly-que of wax protruding from their hind end, a feature Whitney tells me is apparently unique to this one species in the genus.
Psyllid nymph with characteristic "tail" of wax.
Psyllids nymphs, one without wax.
I think this psyllid is a chronic inhabitant of the currant thickets in the woods behind the Lamar Community College and other wooded areas nearby (Arkansas River, Thurston Reservoir, etc.). It does not appear to cause any serious damage to its hosts. But at least this spring, it was clearly a valuable resource for birds in need of fuel during an unusually late and cool spring migration period.
Among the species I was able to observe feeding heavily on this psyllid were: yellow warblers, Wilson's warblers, a rare chestnut-sided warbler, two rare mourning warblers, a rare black-throated blue warbler, several MacGillivray's warblers, a rare blackburnian warbler, a few American redstarts, a Bell's vireo, dozens of Swainson's thrushes, brown thrashers, gray catbirds, a rose-breasted grosbeak, willow flycatchers, a rare alder flycatcher, great crested flycatchers, least flycatchers and Lincoln's sparrows. Probably many others were getting in on the act, also.
Dave Leatherman
Fort Collins
