28 BIEDS OF A MAEYLAND FAEM. 



and several wrens went into the field often, and two Maryland j^ellow- 

 throats scurried among the leaves. Forty birds were killed in the 

 vicinity of tobacco fields. They comprised, for the most part, the 

 several species of native sparrows that breed on the farm, including 

 also a few wrens, meadowlarks, flycatchers, and others. Not one of 

 the 40 had fed on tobacco worms, although observations on the farm 

 at other times had shown that birds eat them as well as other sphinx 

 caterpillars. Bobwhites and vireos take them, but were not repre- 

 sented in the collection. The chipping sparrow had eaten them at 

 other times, the English sparrow had been seen picking them from 

 the plants, and the crow is known to be an habitual ''wormer.' In 

 June, 1900, an old crow and five young staj^ed near tobacco in lot 1 

 for ten days. In the early morning and late afternoon the \^oungsters 

 would sit clamoring on the fence, while the mother bird brought them 

 worms from the field. 



By way of summary it may be stated that while the observations 

 made to determine whether or not the birds of the farm were protect- 

 ing field crops from insects yielded in the main negative results, they 

 do not lead to the conclusion that birds are of no service. They do 

 indicate, however, that birds are not to be depended on to check 

 uprisings of insect pests, and that insecticides should be used freely 

 and repeatedly. In case of this farm it is probable that the super- 

 abundance of May -flies and caddis-flies diverted the birds' attention 

 from pests to the hordes of harmless insects. The pea plant-louse 

 is a new species, unfamiliar to birds, which, however, seldom eat 

 plant-lice. The potato beetle, though unpalatable and avoided by 

 many birds, is eaten with relish b}^ the bobwhite. Had an especial 

 efl'ort been made to collect this bird in infested fields, it would probably 

 have been found to be doing much to reduce the numbers of the pest. 

 Tobacco worms have also been attacked by the bobwhite as well as by 

 the crow, English sparrow, and chipping sparrow; and it is likely that 

 when these worms are small man}" species of birds feed on them. 



INFESTED TREES AND SHRUBS. 



Fall webworm. — The next group of observations concerns insects 

 that attack trees and shrubs. The fall webworm occurred regularly 

 at Marshall Hall. It was most often found on willow, black walnut, 

 mulberry, apple, and pear trees. At a time when it was not especially 

 abundant 62 birds, largely catbirds, sparrows, orioles, warblers, and 

 flycatchers, were collected. One of the orioles, a male Baltimore, had 

 eaten webworms. During the middle of June, 1899, web worms defoli- 

 ated parts of apple and pear trees. A number of stomachs were col- 

 lected and the trees were closely watched, but nothing gave evidence 

 that the pest was being destroyed. During the last of August, 

 1896, it was so abundant that it defoliated all the willows of the hog- 

 lot gully and fairly festooned the branches with webs. The trees were 



