April, 1S93.] 



AND OOLOGIST. 



55 



As previously remarked, the southern 

 limit of this bird as a summer resident is 

 the central part of the State. Here it is 

 found in such limited numbers in the breed- 

 ing season that it is seldom observed. 



The Bobolink is transient throughout 

 the State, as many do not remain in the 

 northern counties, but pass further north. 

 From the material in hand, I cannot say 

 exactly at what date this bird enters the 

 southern extreme of the State in the spring. 

 We find it passing through 75 and 77 in the 

 last few days in April and first and second 

 week in May, but by comparing the arrivals 

 in the south with those in the north, very 

 little, if any, difference in the time is found. 

 Reports from counties 3, 6 and 7 show that 

 the Bobolink arrives the last of April or first 

 week in May. From this it appears that the 

 bird must travel quite rapidly through the 

 southern half of the State. The period of 

 the spring migration in Illinois lasts for 

 about three weeks, viz., last week in April 

 and first two in May. Of course there are 

 exceptional cases of early and tardy arrivals ; 

 note the early date in county No. 33, April 

 loth. Mr. O. Widmann sends such an in- 

 teresting report on the movements of this 

 bird in the spring, that I take the liberty to 

 quote : 



"The Bobolink, a transient visitant with 

 us, is one of the most interesting species for 

 the study of spring migration, for the follow- 

 ing reasons : 



"It is regular in its migration as a bird 

 can be ; it is a very conspicuous bird, can- 

 not be overlooked ; it cannot easily be con- 

 founded with anything else ; males, females, 

 old and young birds are distinguishable. 

 In the neighborhood of St. Louis, its north- 

 ward migration extends over three weeks, 

 from April 28 to May 19, earlier and later 

 dates are rare. The time of their regular 

 transit may be divided into three periods ; 



" First period from their appearance in the 

 last days of April to the fifth of May ; highly 

 dressed males, singly or in small parties, 



always singing, generally seen on wing going 

 north at all hours of the morning. 



" Second period from May 5 to 12; nu- 

 merous troops of 20 to 40 males, some not 

 in full dress yet, and first females, compos- 

 ing 10 to 25 per cent of the troops. Mostly 

 seen on wing, but also feeding on ground or 

 concerting in treetops. 



"Third period; females predominate, 

 sometimes 90 per cent of a flock ; troops 

 of immature males and, toward the end of 

 migration, young females with obviously plain 

 headmarkings. The troops of this period 

 stay sometimes all day at one place, are less 

 noisy and more on the ground feeding. 



" JVJy experience with this species in the 

 fall migration is limited to one record, Sep- 

 tember 14, 1882, a large flock of moulting 

 (blotched) birds on trees in swamp in the 

 bottomland. I do not mean to say that 

 they do not pass through these bottomlands 

 regularly every year ; possibly they do, and 

 probably they do so without staying long at 

 one place, but my visits to these places were 

 too unfrequent and irregular. All I know is 

 that they do not pass over the same grounds 

 which they visit in the spring." 



Mr. George B. Holmes also reports that 

 the males precede the females. 



In the spring migration, the Bobolinks 

 move in small flocks of ten to thirty individ- 

 uals each, pausing here and there to feed 

 and rest, and the males making the mea- 

 dows ring with the renowned Bobolink song. 



Of the fall migration, data is so meagre 

 that I am not warranted in advancing any 

 statements or forming any definite conclu- 

 sions. The majority of the reports contain 

 nothing on the fall movements of this bird. 

 This is not surprising, for the reason that 

 many of the contributors probably do not 

 recognize the bird in its duU winter plu- 

 mage. Mr. B. T. Gault, of county No. 8, 

 reports that the Bobolink commences to as- 

 sume its winter plumage in the last of July. 

 Mr. Widmann's only fall record was made 

 on a large flock of moulting birds. 



