44 



ORNITHOLOGIST 



[Vol. 15-No. 3 



brings with it one, whieli was seen and well 

 identified Nov. 2, 1889. 



The welcome voice of the Shore Lark was 

 first heard Feb. 3, 1800. Owls have been com- 

 mon and the winter has been one which has 

 furnished many notes of interest. 



C. H. ParkhlU. 

 Cornwall. Vermont. Feb. 8, 1890. 



A Discussion of the Terms Used to 



Denote the Relative Abundance 



of Birds. 



It seems to be a very perplexing problem 

 among many ornithologists how to treat the 

 relative abundance of birds, and tlie subject 

 seems to be one of the yet unsolved questions, 

 although there has been a vast improvement 

 during tiie last few years. 



Ten or fifteen years ago tlie ornithologists' 

 vernacular describing the reiative numbers of 

 birds was in a most chaotic; state, best under- 

 stood by reviewing some of the terms most 

 used at that time, for example, "rather com- 

 mon,'' "a few," "not many," "a fair sprink- 

 ling," et(\, whicli if taken literally mean either 

 nothing at all, or are so ambiguous that they 

 convey no lucid idea of the authors meaning. 



To the early efforts of the "A. O. U.," as 

 seen in the blanks prepared for the record of 

 migrations, and later those issued by the Agri- 

 cvxltural Department, we owe much of the 

 present order of systematic nomenclature of 

 terms, and without (piestion they are the best 

 that have yet been used, and in most cases 

 they are as explicit as is practicable, although 

 the term "accidental" is sometimes necessary, 

 and like the other four has the advantage of 

 expressing everytliiug desired to be known in 

 a single word. 



Although these terms of "abundant," 

 "common," " tolerably common," and "rare," 

 are certainly got)d, it seems necessary to give 

 thein some furthei' modilication, for to affirm 

 that a certain hawk and a certain warbler are 

 both common does not give an adequate con- 

 ception of the relative abundance of each 

 species. In other words the term does not 

 modify tlie relative difference in nundiers be- 

 tween the two birds, but describes the ratio 

 existing between birds of the same family or 

 group, or between birds governed Ijy the same 

 conditions of existence; that is, it cannot be 

 expected that there would be as many hawks 

 as there are warblers, because, in a measure, 

 these warblers and other small birds constitute 



the food supply of the raptores, and therefore, 

 if the contrary were true, the whole race of 

 hawks would be in great danger of extermin- 

 ation as soon as each had devoured its allotted 

 sparrow. A good illustration of what I mean 

 may be found by turning to any of the num- 

 erous local lists of recent date, and the follow- 

 ing extracts taken at random will serve as 

 good types: 



"American Ooldtinch. Resident; common." 

 "Pine Siskin. Winter resident; rare." "Song 

 Sparrow. Resident; abundant." "Lincoln's 

 Sparrow. Summer resident; rare." "(Joop- 

 er's Hawk. Resident; cominon." "Red- 

 shouldered Hawk. Resident; tolerably 

 common." 



Thus, in the case of the two Spinidce, we 

 readily grasp the author's meaning when he 

 classes one as common and the other as rare, 

 because we know that both species have 

 similar habits, and one is rare only in com- 

 parison to the otlier. 



The same ajiplies to the two Song Sparrows. 

 One is rai'e when compared with the other, 

 but a comparative rarity can not be drawn 

 between them and the goldfinches, inst)much 

 as the habits of the two genera are dissimilar, 

 for one is highly gregarious in its character- 

 istics, and the other is usually found in pairs, 

 or at most in family scpiads, so that though 

 one miglit, on a winter's day, see ten Siskins 

 to one Song Sparrow, that fact alone would 

 not admit the reversion of the terms, viz. : to 

 call the Pine Finch common and tlie Song 

 Sparrow rare, although in actual numbers it 

 w(nild be true. On this ground the relative 

 abundance of the Song Sparrow and Finch can 

 not be estimated, as both have equal right to 

 the same modifying term. 



In the case of the two raptores the rule of 

 family comparison is the same, but when 

 compared to the other birds, even to the Song 

 Sparrows, which, like themselves, are usually 

 non-gregarious, it loses all force. One feeds 

 upon seeds and insects, of whicli there is a 

 varied aud never ending supply, capable of 

 supporting a large number of individuals, but 

 the other feeds on the birds themselves (to a 

 greater or less extent), and therefore the laws 

 governing the existence of each are entirely 

 unlike, therefore we might see one hawk to 

 a dozen sparrows and still class both under the 

 same heading when referring to either as being 

 rare or common. 



On this account it is necessary to make some 

 distinction between birds of gregarious habits 

 and those which are disposed to pursue solitai y 



