>From Birds of North America subscription regarding Bushtit diet it reads ...
"Diet Stomach contents of 353 Bushtits in California revealed 81% animal material (insects and spiders) and 19% vegetable matter by count; little variation among months (Beal 1907). However, Mar and Nov stomachs contained fewer animal food items (53%) and Apr and Jun stomachs exhibited 100% animal material. Scale insects (Coccidae) were most abundant food item taken (19%). Of total food items, animal matter (81%) 44% composed of Hemiptera (true bugs, including scale), >10% Coleoptera (beetles), 16% Lepidoptera (mostly caterpillars and pupae), <1.5% Hymenoptera (wasps and ants); remaining 8% made up mostly of spiders and some insects. Less than 1% of food was fruit; remaining vegetable matter consisted primarily of small galls (probably for the contents) and tiny seeds (Beal 1907). Since theses data are counts of individual food items, they may not adequately reflect relative caloric importance. For this reason, and because diet information is sparse and dated, this aspect of Bushtit life history certainly deserves further attention. Bushtit has been observed eating olives in California (Bent 1946) and willow seeds (Salix lasiolepus) in Arizona (SAS). Geometrid larvae have been suggested as most frequently taken item for both adult and nestling (San Mateo Co., CA; Hertz et al. 1976) based, however, on visual observation of foraging success, not on stomach content. Since these larvae are much more visible than the scale insects on which Bushtit feeds abundantly, this is likely an overestimate of frequency of lepidopteran larvae taken. Lepidopteran larvae are a rich food source, however, and may be far more valuable to a foraging Bushtit than scale insects. Nestlings fed a higher proportion of lepidopteran larvae and pupae (80%) than reflected in adult diet in California; remainder of nestling food comprised of 2% beetles, 2% wasps, 8% bugs, and 7% spiders (stomach contents; n = 8 nestlings; Beal 1907)." Recommended Citation: Sloane, Sarah A. 2001. Bushtit (Psaltriparus minimus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/598 doi:10.2173/bna.598 Thanks Gary Lefko, Nunn/CO http://ColoradoBirder.ning.com/ -- Home of "NunnCAM" On Feb 8, 3:15 pm, "Dave Leatherman" <[email protected]> wrote: > Did my normal circuit from Prospect and Sharp Point south thru Prospect Ponds > Natural Area to the Environmental Learning Center (ELC) back north across the > river thru Cottonwood Hollow Natural Area west to the starting area. > > Highlights: > BUSHTIT (flock of about 18 birds, first time I've ever seen them along the > Poudre in the Fort Collins area in several hundred visits over the last 35 > years) > Hooded Merganser (1 male in the canal just west of the long unpaved lane that > leads to the ELC parking lot) > Wood Duck (at least 5 at various locations) > Northern Shrike (1 at Cottonwood Hollow near the info kiosk) > Northern Pintail (6 at Cottonwood Hollow) > Killdeer (heard) > Great Blue Heron (3) > Red-tailed Hawk (2 in love, sitting next to eachother on a high power line > tower) > > I would love to know what bushtits eat. They are always in groups. They are > always on the move. Their foraging style reminds me of the school kids I > withstood recently at the Arizona-Sonora Desert Museum: you can hear them > coming from a long ways away, little high-pitched squeals and bell-like > notes, then you see them flitting along, soon they are all around you, > stepping on your feet, hands on glass, impatient, looking here and there, > loud, and just like that - gone. How could they ever find enough aphids or > spider egg sacs or whatever to sustain their ADD-type activity? Surely > bushtits have moved along the Poudre River in Fort Collins more than just > once since 1974, but if a person wasn't there during exactly the right > 5-minute period, it's hard to detect vapor. > > As an aside, today the resident Northern Flicker in my courtyard on the east > side of Fort Collins did his territorial drumming for the first time (at > least that I've heard) this spring. This seems early (maybe because I dread > waking up at dawn for the next several weeks, whether I have a reason to get > started on the day's activities or not). In checking my journals, while this > is the earliest date for drumming (by a few days), there are several entries > that indicate either mating calls or drumming were noted in the courtyard > sometime in February or early March. > > Dave Leatherman > Fort Collins --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/cobirds?hl=en -~----------~----~----~----~------~----~------~--~---
