134 THE CONDOR Vol. XXIII 
Abnormal Egg of Western Lark Sparrow. In my collection is a set of eggs of 
the Western Lark Sparrow (Chondestes grammacus strigatus) taken on June 26, 1920, 
at Claremore, Oklahoma, which contains two normal eggs, one normal Cowbird egg, and 
one extremely large Lark Sparrow egg. This large egg is marked similarly to the 
other two and measures .95 by .67 inches. Reed gives the average size of eggs of this 
species as .80 by .60 inches.—J. R. PEMBERTON, Tulsa, Oklahoma, April 13,1921. 
Relative Dimensions of Aeroplanes and Hawks.—It has been the writer's experi- 
ence that the majority of the hawks observed by bird studenis are seen in flight, usually 
outlined against the sky. The proportional dimensions of a bird can usually be made 
out, but it is often impossible even for an expert to be sure about the color or markings, 
especially when the bird is seen against a strong light. We say that a Cooper Hawk has 
a long tail or that another hawk has long wings, but these members are long or short 
compared with—what? It would certainly be more exact to say that in the Cooper 
Hawk the length (the distance from tip of bill to end of tail) is 60 percent of the spread 
of the wings. 
It is a well-known fact that female hawks are larger than males; but measure- 
ments show that the ratio of length to spread is about the same in both sexes. This 
matter of proportion appears to be constant in any given species, irrespective of sex 
and age, in all full-feathered individuals. Using the ratio of length to spread as a 
basis, we find that the various species of hawks found in Catifornia may be readily 
separated into two groups, those that have a length greater than one-half of their spread 
and those that have a length less than one-half of their spread. With the exception 
of the falcons, we may safely say that the harmful species can all be piaced in group 1 
and the beneficial species in group 2. For example, the Cooper Hawk, regarded every- 
where as harmful, has a length 60 percent of its spread, while the beneficial Swainson 
Hawk has a length that is only 40 percent of its spread. (See accompanying table for 
further figures. ) 
TABLE) SHOWING RATIO OF LENGTH TO SPREAD IN VARIOUS SPECIES OF 
HAWKS AS SHOWN BY MEASUREMENTS OF BIRDS IN THE FLESH 
Average ratio, 
Genus Species length to spread 
Cooper Hawk .= 22"... a eee 60% 
Accipiter Sharp-shinned Hawk. ...........22222.....22222200----- D4% 
Gosha wit. 5255 28 ese oe ee eee D296 
SDarrow., Haiwikens eee rere ATG 
Pigeon (Hawk 2... 5 2 oe ee 45% 
Falco ; 
Duck. Hawke = ".< 263 ee ee 44% 
Prairie “Paleon: \.2 o 3. oe eee 43% 
Circus { Marsh, ‘Hawken eee eee 42% 
Red-tailed “Hawk... 34.23 eee 42% 
Buteo SHG W OOS COpON JRE ALe ch ee ee 40% 
Archibuteo } Rerruginous Rough-leg a... eer 40% | 
Pandion { OSDIGY stipes, st 2.2 oe ee ee 39% 
Regarding the relative proportions of aeropianes and hawks, it may be staied 
that, in general, aeroplanes are relatively longer than hawks, the ratio of length te 
span in the former being, in ascertained cases, from 54 to 80 percent. In the recent 
four-passenger, Orenco type F, Tourister Aeroplane, as illustrated in Aerial Age of May 
3, 1920, page 2538, the over-all length is 25 feet, 10 inches, and the span 38 feet, a ratio 
of length to spread of 68 percent. The Cooper Hawk has nearly the same proportions 
as this modern aeroplane; and the harmful bird-hawks (Accipiters) might well be called 
aeroplane-hawks to distinguish them from the short-tailed squirrel-hawks (Buteos), 
which are beneficial—JosrrH Drxon, Museum of Vertebrate Zoology, Berkeley, Califor- 
nia, June 10, 19217. 
