The Relative Size of Eggs of the Red- 
tailed Hawk to the Parent Bird. 
In no work on Oology with which the present 
writer is acquainted has the very interesting 
question of the relative size of the parent birds to 
their respective sets of eggs been considered. In 
the present article it is proposed to give the 
measurements of a series of eggs of the Red-tailed 
Hawk, ( Buteo iorecdis ), together with the size of 
the female parent ot each set. In each case the 
female was shot as she flew away from the nest, 
and the skin preserved with the eggs. The 
parent birds and the eggs are in the cabinet of 
F. II. Carpenter, who has very kindly furnished 
all the measurements, notes, etc. Al! the meas- 
urements are in inches, and any credit which is 
due for the idea of this article should be given to 
Mr. Carpenter ; who not only conceived it but fur- 
nished tire writer with the material to carry out 
the theory. 
I. Bristol County, Mass., April 7, 1884. Two 
eggs. No. 1 : 2.43x1.81. No. 2: 2.35x1.80. Dull 
colored specimens. No. 1, marked with a few 
blotches of brown evenly dispersed over the egg. 
No. 2 has the brown spots centred about the 
larger end. Female bird measures: Length, 22 
5-16 ; expanse, 51 9-16. Very poor in llesh. 
II. Berkshire County, Mass., April 11, 1883. 
Two eggs. No. 1 : 2.28x1.75. No. 2 : 2.30x1.77. 
No. 1 is marked with a single large dull brown 
blotch on large end, and the ground color is dirty 
white. No. 2 has the ground color dull white, 
streaked with drab, and is a very plain egg. 
Female bird measures: Length, 21 10-16 ; expanse, 
49 2-1G. In fair condition. 
III. Berkshire County, Mass., April 11, 1883. 
Two eggs. No. 1: 2.33x1.87. No. 2: 2.37x1.90. 
No. 1 is bluish white, with a few small brownish 
spots. No. 2 is bluish white, unmarked. Female 
bird measures: Length, 23 4-16; expanse, 51 13-1G. 
In very poor condition. 
IY. Eastern Connecticut, April 8, 1882. Two 
eggs. No. 1 : 2.28x1.90. No. 2 : 2.34x1.80. No. 
1 is marked with large splashes of bright brown, 
stained, and No. 2 is marked with a few purplish 
spots on a dull white ground color. Female bird 
measures: Length, 23 12-16 ; expanse, 52 8-1G. In 
fair condition. 
V. Eastern Connecticut, April 11, 1882. Two 
eggs. No. 1: 2.41x1.96. No. 2: 2.38x1.92. No. 
1 is bluish white, unmarked, but very much 
stained, while No. 2 is entirely different, having 
heavy large blotches of brown on a dull white 
ground. Female bird measures : Length, 24 5-6; 
expanse, 53 14-16. In very fair condition. 
VI. Central New York, April 13, 1881. Two 
eggs. No. 1: 2.46x2.01. No. 2: 2.43x1.93. Both 
are very similar in appearance, and beautifully 
marked with reddish brown blotches on a bluish 
white ground color. Botli the parent birds lived 
luxuriously on the offal of a slaughter house, 
which was not far from the nest. Female bird 
measures: Length, 24 14-16; expanse, 55 3-16. 
Very fat. 
VII. Central New York, April 14, 1881. Two 
eggs. No. 1 : 2.39x1.87. No. 2 : 2.36x1 91. No. 
1 is marked with dark brown blotches, and No. 2 
is bluish white, stained, and has a few brown 
spots about the larger end. Female bird measures : 
Length, 22 12-16 ; expanse, 50 5-16. In poor 
condition. 
VIII. Western Connecticut, April 12, 1882. 
Two eggs. No. 1 : 2.23x1.82. No. 2 : 2.28x1.78. 
Buteo borealis: April 1, three sets of two, 
Broad Brook, Holme’s Woods, and Quinebaug 
River. April 13, two sets of two, Lime Rock 
Woods and April 17., set of two, 
Lantern Hill.jjJ- 7%. t C<yiw. 
O.&O. X. Feb. 1885. p.AiT 
No. 1 is dull white, marked with a few purplish 
and brown blotches, while No. 2 is marked with 
bright brown spots about the larger end. Female 
bird measures: Length, 20 11-16; expanse, 47 
8-16. Very fat. 
IX. Western Connecticut, April 13, 1882. Two 
eggs. No. 1 : 2.39x1.83. No. 2 : 2.41x1.87. No. 
1 is bluish white, with a few brownish spots about 
the smaller end. No. 2 is of the same ground 
color, but is unmarked. Female bird measures : 
Length, 22 4-16 ; expanse, 53 11-16. Fat. 
X. Berkshire County, Mass., April 8, 1883. 
Two eggs. No. 1: 2.29x1.86. No. 2 : 2.34x1.84. 
No. 1 is dull white marked with a few purplish 
spots about the larger end, while No. 2 is dull 
white, with a few nearly obsolete spots about the 
larger end. Female bird measures : Length, 24 ; 
expanse, 53 3-16. In very poor condition. 
XI. Bristol County, Mass., April 13, 1885. Two 
eggs. No. 1 : 2.33x1.88. No. 2 : 2.40x1.79. No. 
1 is dull white, marked with a number of small 
reddish brown spots. No. 2 is also dull white, 
but has a number of brown spots about the larger 
end. Female bird measures : Length, 24 13-16 ; 
expanse, 54 7-16. Very fat. 
It will be seen, from an examination of the 
above measurements, that the size of the eggs 
seems to depend on the size of the female parent, 
for while No. VIII (the smallest bird) measured 
only 20 11-16x47 8-16, the eggs measured 2.23x 
1.82 and 2.28x1.78; and in the case of No. VI (the 
largest) the female measured 24 14-16x55 8-16, and. 
the eggs 2.46x2.01 and 2.43x1.93. All the other 
eggs bear relative proportions of size to their 
female parents, and this interesting fact may be 
considered as established beyond dispute by the 
foregoing measurements. The larger the bird 
therefore the larger will be the egg for that 
species, and vice versa. Of course in the event of 
the birds being deprived of their eggs, the second 
or third set laid would probably be smaller, and 
the rule would not hold good. The dates at 
which these eleven sets of eggs were taken, and 
the parents shot, forbid the supposition that any 
of them could have been second sets. 
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Green Eggs of the Red-tailed Hawk. 
The eggs of the Red-tailed Hawk (Buteo bo- 
realis) have a ground color which varies from 
white through grayish-white to a faint bluish- 
white, but a set of eggs of this species which 
exhibit a decided greenish tint must be con- 
sidered a novelty. 
Such a set has, however, been taken, and 
they are now before me. They were collected 
on April 22, 1888, by the celebrated oologist 
“.I. M. W. ” (Mr. C. L. Rawson) in New Lon- 
don County, Connecticut, and fully identified. 
The ground color is of a pale, but decided 
greenish tint, and both the eggs are spotted 
near the ends with fawn color. The greenish 
tint of the ground color is distinctly percepti- 
ble, especially by daylight, and is all the more 
remarkable when seen in a large series of eggs 
of this bird. Out of thirty-six sets now before 
me (containing eighty-six eggs) these two are 
the only ones which approach to a greenish tint. 
As if to make the set still more remarkable 
one of the eggs is a decided runt, and only 
measures 2.01x1.60, while the other is of 
normal size, and measures 2.37 xl.85. 
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