Notes from Field and Study 



91 



the chief visitors to the trough, I have also 

 Mourning Doves, Crows and some other 

 common birds there apparently eating 

 fragments of salt. I have given salt to 

 chickens and find that they eat it greedily. 

 The above notes are not by any means 



conclusive, and if the fact that birds like 

 salt has not already been established, 

 it should offer some opportunities for 

 interesting experimental work at feeding 

 stations, etc. — Fred J. Pierce, Winthrop, 

 Iowa. 



THE SEASON 

 XXIV. December 15, 1920 to February 15, 1921 



Boston Region. — The winter in 

 Massachusetts has been mild, so far, with 

 very few cold days. About Boston the 

 ground has been bare, or covered by only 

 two or three inches of snow. These con- 

 ditions are in marked contrast to those 

 of last winter when periods of intense 

 cold were protracted and the snow-fall 

 was over ten times as great. 



The scarcity of birds reported two 

 months ago has been no less noticeable 

 during January and February. Not only 

 is there a total absence of the irregular 

 winter visitors, the Grosbeaks, Redpolls, 

 and the Crossbills, but in this region 

 there are very few of the usual winter 

 visitors, such as Tree Sparrows, Juncos, 

 and Golden-crowned Kinglets. Permanent 

 residents also — Chickadees and White-bel- 

 lied Nuthatches for example — are present 

 in numbers far below normal. During 

 midwinter excursions into the country, 

 although the sun shone brightly and the 

 air was soft and spring-like, we found the 

 woods and thickets deserted, and for mile 

 after mile as silent as midnight. 



This absence of birds set us thinking, 

 wondering where the birds are which 

 usually spend the winter with us, and why 

 they did not move southward this season. 

 Observers who visited northern localities 

 last autumn reported a good crop of pine- 

 cones there, and hence predicted that 

 there would be no invasion of Crossbills 

 into New England; perhaps the successful 

 fruiting of birches, alders and other trees 

 similarly accounts for the absence of Red- 

 polls and Pine Grosbeaks. 



Mr. Edward H. Forbush advances the 

 ingenious explanation of the rarity of 

 the smaller passerine birds which usually 



winter here. He says in Bulletin XXXVII, 

 Division of Ornithology (Mass.), Jan. 31, 

 1921: "Perhaps this [scarcity] may be 

 accounted for in part by the fact that many 

 individuals that were accustomed to stay 

 here were killed off by the severe weather 

 of last winter." This suggestion becomes 

 very significant when considered in the 

 light of Mr. S. Prentiss Baldwin's discovery 

 that many individual birds pass the winter 

 in definite localities. 



The Evening Grosbeak has become, of 

 late years, such a regular winter visitor 

 in eastern Massachusetts that some 

 explanation other than the abundance of 

 food in the North seems necessary to 

 account for its non-appearance this year. 

 The favorite food of this Grosbeak while 

 wintering here is the seed of the box elder 

 {Acer negundo) and it has been suggested 

 that extensive planting of these trees 

 between New England and the Great 

 Lakes has resulted in inducing the birds 

 to extend their winter range toward the 

 southeast. Examination of the fruit of the 

 box elder trees in Lexington, Mass., shows 

 that, although the trees appear to have 

 ripened seeds this winter, a large propor- 

 tion of the embryos are so withered that 

 they would be worthless as food for the 

 Evening Grosbeak. The failure of this 

 crop of seeds, if at all general, may be 

 responsible for the absence of this bird 

 from New England. 



If observers who live on the Grosbeak's 

 line of travel to the Atlantic Coast will 

 examine the seeds of the box elder in their 

 respective localities and report the results 

 to me, I shall be glad to summarize them 

 for publication. — Winsor M. Tyler, Lex- 

 ington, Mass. 



