NORTHERN BLACK-THROATED BLUE WARBLER 231 



tioned as food for the young are also eaten by the adults. Forbush 

 (1929) adds the hairy tent caterpillar, flies, beetles, and plant lice. 

 Aughey (1878) found 23 locusts and 15 other insects in one stomach 

 collected in Nebraska. Dr. Wetmore (1916) reports on the contents 

 of eight stomachs collected in Puerto Rico, in which animal matter 

 formed 75.5 percent and vegetable matter 24.5 percent of the food. 

 "The vegetable food was found in the three stomachs taken in Decem- 

 ber and January and consisted of seeds of the camacey {Miconia 

 prasina).^^ The principal items in the animal food were lantern 

 flies (Fulgoridae), 19.46 percent, various weevils, 14.25 percent, flies, 

 10.09 percent, and spiders, 12.62 percent. A few beetles and one ant 

 were eaten. Most of the food consisted of harmful insects. 



Behavoir. — The black-throated blue warbler is one of the tamest and 

 most confiding of all our wood warblers. I was able to photograph 

 (pi. 30) the female incubating and both sexes feeding the young at 

 very short range without any special concealment; they are very 

 devoted parents and show great concern when the safety of their 

 young is threatened, trailing along the ground with the broken-wing 

 act in great distress. 



Gerald Thayer wrote to Dr. Chapman (1907) : "In its movements 

 the Black-throated Blue is more deliberate than many of its relatives, 

 but it has at the same time a somewhat Redstart-like way of 'spiriting' 

 itself from one perch to another, and, while perched, of partly opening 

 its white-mooned wings ; — a habit and a marking shared by the boldly 

 blue-and-black-and-white males and the dimly green and yellowish 

 females and young." 



Henry D. Minot (1877) writes: 



They are very dexterous in obtaining their insect prey ; sometimes seizing it 

 In the air, with the skill of a true Flycatcher, and at other times finding it among 

 the branches of the various trees which they frequent. Now they twist their 

 heads into seemingly painful postures, the better to search the crannies in the 

 bark or blossoms, now spring from a twig to snap up an insect in the foliage 

 above their heads, instantly returning, and now flutter before a cluster of open- 

 ing leaves, with the grace of a Hummingbird. Occasionally they descend to the 

 ground, and are so very tame that once, when I was standing motionless, ob- 

 serving some Warblers near me, one hopped between my feet to pick up a 

 morsel of food. 



Voice. — Aretas A. Saunders has sent me the following study of the 

 song : "The song of the black-throated blue warbler, in its more typi- 

 cal forms, is one of only three or four slowly drawled notes in a pe- 

 culiarly husky voice, the last note commonly slurred upward. While 

 the number of notes in the songs varies in my 41 records from two to 

 seven, more than half of them are of only three notes, and most of the 

 others are of four or five. In all, 22 songs end with the upward slur 

 of the last note, 14 in an unslurred note and 5 in a downward slur. 



