138 



THE OOLOGIST. 



that the Northern birds are much 

 larger, lay larger eggs, and the ests 

 contain more eggs. This is especially 

 true of the Redwings which lay four 

 eggs almost invariably in the north 

 and occasionally five. In the extreme 

 south the Redwing is content to lay 

 two or three eggs which are smaller. 

 Now for the Great Blue Heron: 



Northern sets of Ardea herodias 

 have more and smaller eggs, south- 

 ern sets fewer and larger eggs, but 

 the southern birds can be accused of 

 laying two sets a year, while the best 

 the northern birds can do is to raise 

 one brood a year. The birds mention- 

 ed in the preceding paragraph are 

 nearctic in their affinities, and there- 

 fore flourish best in a northern cli- 

 mate, where their environments are 

 better adapted to them. But the 

 herons are neotropical and as soon as 

 they go north they deteriorate. How- 

 ever in order to maintain themselves 

 in a less favorable environment, they 

 must lay more eggs, which are small- 

 er and are liable on that account to 

 produce less hardy young. 



The southern heron lays fewer and 

 larger eggs, producing hardier young 

 which have a greater chance of exist- 

 ing. The southern Redwings produce 

 fewer young in a less favorable en- 

 vironment, but are able to reproduce 

 more than once, which explains the 

 small southern sets of the Redv/ing. 

 In the north one slightly larger brood 

 is as advantageous as two smaller 

 broods in the south, for a nearctic 

 bird, while a neotropical bird must 

 produce one larger brood in the north 

 because environment is not so favor- 

 able and time for reproduction is 

 much more limited. 



Very truly yours, 



Chas. S. Thompson. 



Possibly true. It's worthy of in- 

 vestigation anyway. A hasty exam- 

 ination of my large series of Crows' 



Eggs confirms Mr. Thompson's state- 

 ments regarding them. Evidently 

 the decrease in size of birds militates 

 against the smaller size of sets and 

 prevents increase in size of eggs in 

 the small Southern sets of Crow. — 

 [Ed.] 



"On the Haunts of the Swainson's 

 Warbler." 



M. T. Cleckley, M. D., 



Augusta, Ga., 1907, 35c. 



Pressure of other matters has de- 

 layed a review of this interesting 

 pamplet some weeks. In a neatly 

 printed pamphlet of 9 pages and cov- 

 ers Dr. Cleckley reviews his experi- 

 ences with this bird since he first dis- 

 covered it as a local breeder on May 

 30, 1903, describing the habits. Song 

 and Food and noting the acqquisition 

 during five seasons of about twenty 

 sets aggregating 73 eggs. There are 

 three plates of nests and eggs in 

 situ and one plate of eggs. The sec- 

 ond plate is very good as to detail. He 

 did not succeed in photographing 

 Madame Swainsoni at home. 



The nature of their habitat would 

 make this difficult of course. Evi- 

 dently this bird must be more plenti- 

 ful in the almost impenetrable 

 swam;:s of this region than recorded. 



He does not record any sets over 



3 eggs. Apparently 3 is normal for 



Swainsoni as probably for bachmani. 



Ernest H. Short.. 



Edithor Oologist: — 



While sets of five eggs of the Amer- 

 ican Robin are being recorded I take 

 the liberty of adding my experience. 

 I have a record of every robin's nest 

 found by me during the last twenty - 

 one yf-ars and no nest of young held 

 more than four and but one neat cf 

 eggs contained five. This was seenr- 

 ed May 30, 1899, and is in my col- 

 lection. The eggs are a trifle less 

 than the average size and of the long 

 narrow type but being uniform in size 



