EASTERN BLUEBIRD 251 



until the young of that brood have left the care of the parents and 

 it is time to start a new nesting. 



"The call notes of the bluebird are fully as musical as the song. 

 These notes may be 2- or 3-syllabled, oola, aloo, oolaloo, or aloola. 

 They may be heard frequently in the fall migration, as flocks of the 

 birds fly over in October and November. The alarm note, given 

 when the young are just out of the nest, is the only harsh sound 

 I have heard from this bird; it sounds like chat or is often doubled 

 to chatat." 



Mr. DuBois (MS.) writes the fall note as juiiit or Juliet, which 

 seems to be a good rendering of it. I have heard this plaintive fall 

 note early in spring, before the real song season begins. To John 

 Burroughs (1871) the bluebird seems to say "Bermuda! Bermuda! 

 Bermuda!" The song has often been expressed in other syllables, 

 such as turwy, cherwee, cherey-lew, or tura-lee, in soft, liquid, musical 

 tones. W. E. Saunders (1887) once heard, and saw clearly, a blue- 

 bird imitating the kay-kay note of the blue jay; he "found that after 

 the bluebird had warbled from four to seven times, the next warble 

 would be prefaced with the Jay note." 



The bluebird has about the lowest-pitched voice of any of the 

 passerine birds; the crow's voice is decidedly lower, and that of the 

 Baltimore oriole is slightly lower on the average but has a higher 

 range. According to Albert R. Brand (1938) the bluebird's voice 

 has an average mean frequency of 2,550, a maximum of 3,100, and 

 a minimum for the lowest note of 2,200 vibrations per second. 



Enemies. — Bluebirds seem to have no human enemies; everybody 

 loves the gentle birds and appreciates that they are very useful and 

 harmless tenants in our orchards and about our farms and gardens. 

 But they have plenty of natural enemies to contend with. Cats 

 readily climb to many of their most accessible nests and can reach in 

 and pull out the young or the incubating parent; snakes climb into 

 some cavities and destroy the eggs; red squirrels and blue jays invade 

 the nests and eat the eggs or young; and house wrens often puncture 

 the eggs, so as to appropriate the nest. Mrs. Laskey (1942) reports 

 for that season: "A total of 174 sets, 774 eggs, were laid. From this 

 large number only 261 young, 33.7 percent, left the nest box safely. 

 Predation was heavy, 81 nests being entirely unsuccessful. Among 

 these, 18 mother birds and 46 nestlings are known to have been 

 destroyed by cats and 55 eggs failed to hatch through the loss of the 

 incubating females. A boy robbed 11 nests of eggs; 42 were rifled of 

 their contents by snakes. A 54 inch specimen collected in one of the 

 boxes last year after eating the young was identified by Dr. Jesse M. 

 Shaver, Peabody College, as a Southern Pilot snake (Elaphe obsolete, 

 obsoleta." 



