ECONOMIC RELATIONS OF OUR BIRDS. 
503 
35. Dendrceca coerulescens (Linn.), Bd. BLACK-THROATED BLUE 
WARBLER. Group I. Class a. 
Migrant. I have not found it common. Its favorite haunts are among the 
heavy timber, but it also visits groves, low, damp thickets, and village shade- 
trees. A considerable portion of its food is gleaned from the bark of the 
larger branches of trees. It poises itself, upon the wing, humming-bird-like, to 
remove insects fi’om the under sides of large limbs, and I liave seen it light 
upon the trunks of trees for the same purpose. Dr. Brewer states that it is an 
expert catcher of small-winged insects. One of these birds came into the 
school-room at Berlin in May, 1875. 
Food: Of six specimens examined, all had eaten insects; one, two ants; five, 
beetles; and one, two caterpillars. 
Larvse, the eggs of insects and spiders (Brewer). 
36. Dendrceca ccerulea (Wils.), Bd. CERULEAN WARBLER. Group IL 
Class a. 
Mr. Nelson, in his “Birds of Northeastern Illinois,” says of this species: “A 
regular but rare migrant. May 12th to 20th, and the first of September. Prefers 
high woods. Rare summer resident here, but near Detroit, Michigan, I am in¬ 
formed it is one of the common species at this season.” Of its occurrence in 
Wisconsin, Dr. Hoy says: “ Not common. A few breed.” 
37. Dendrceca coronata (Linn.), Gray. YELLOW-RUMPED AVARBLER. 
Group I. Class b. 
This Warbler, like most of its genus, is only a migrant. A few may breed in 
Northern AVisconsin, for I obtained a male at Elk Lake in Chippewa county, 
July 26, 1876. 
During the fall, from the middle of September until well along toward No- 
vembei', it is extremely abundant, when it may always be seen in dry open fields, 
along fences and roadsides, and often in orchards and gardens about dwellings. 
On cold, windy days it often hops and flits about porches and windows in quest 
of flies. It also occurs in groves, woods, and tamarack swamps. It is an adept 
at catching insects on the wing, but it secures more of the steady flying coleop¬ 
terous forms than those which have a jerky, zigzag flight. 
Food: Of twenty-one Yellow-rumped Warblers examined, one had eaten a 
moth; two, twenty-one caterpillars — mostly measuring-worms; five, fourteen 
diptera, among which were three tipulids; fifteen, forty-eight beetles; one, four 
of the Ichneumonidae; one, a caddis-fly; one, a spider; and one, fifteen tipulid 
eggs. As these eggs were found in the stomach with the tipulids, they, beyond 
question, were not eaten separately. From the stomach of one bird was taken 
a single tamarack seed. 
Five specimens examined by Prof. Forbes gave evidence of having eaten 
hymenoptera, among them ichneumons; caterpillars; beetles, among which were 
leaf-chafers and long-horns; diptera, hemiptera, spiders and seeds.] 
Larv£8, and berries of wax my idle (Wilson). Caterpillars and berries of wax 
myrtle (De Kay). Spiders, insects and their larvae (Audubon). 
38. Dendrceca BlackburnitE (Gm.), Bd. BLACKBURNIAN AVARBLER; 
HEMLOCK AVARBLER. Group I. Class a. 
This beautiful species, while among the uppermost branches of high open 
woods, reminds one both of the Redstart and the Black-and-white Creeper, whose 
