178 
[Vol. 7-No. 23 
OKNIT 
circle. The wall of the nest is f?enerallv 
thicker at one end of the ellipse than else¬ 
where. 
Six of the seven nests contained three 
egga each, the other but two. Dr. Cooper 
and Capt. Bendire, the only naturalists who 
ajii^ear to have found the nest of this spe¬ 
cies before me, never found more than two 
eggs in a set. Dr. Cooper found a single 
nest near Fort Mojave, on April 27. Capt. 
Bendire, in the season of 1872, found four¬ 
teen nests in the vicinity of Tucson, Ari¬ 
zona, and not one contained more than two 
eggs, “ and in three instances the nest con¬ 
tained but a single egg and the bird hard 
setting upon that.” Some of the nests he 
found saddled ujmn a limb after the man¬ 
ner of other flycatchers, some between 
dead bark and the trunk of the tree, and 
again he found the nest fixed in between a 
lot of young sprouts of a mesquite tree. 
The nests found by him were ol)tained be¬ 
tween May 16 and June 24. 
Capt. Bendire, in a letter to me regarding 
this bird, in speaking of our entirely dif¬ 
ferent observations regarding the number 
of eggs laid by it, gives the following ex¬ 
planation, and I may add that his views 
seem most reasonable and are undoubtedly 
correct He says: “ Tlie small number 
found by me is unquestionably due to the 
fact that iu Southern Arizona they raise 
two and jjerhaps three broods, while in 
California, where we found them, tliey 
raise but one. This I know applies to such 
species as the Icteria vireiis loiujicandit 
and others also whose range in Summer is 
extensive. Here (Fort AValla Walla) this 
species (Long-tailed Chat) always lay four 
eggs, while iu Arizona three is the nile, 
and the latter are considerably smaller. 
Wh}’ the latter should hold good, too. I am 
not so sure about, but I can readily see 
why this specie lays fewer eggs to the set ; 
raising two or three broods a season fully 
makes up for this.” 
Of twenty eggs obtained by me I took 
measurements of fifteen, five having been 
.OGIST 
sent away before I had an opportunity of 
measuring them. The fifteen measure as 
follows; — set (1), .90x64, .92x.62, and 
.89x.62; set (2), .95x.67, .92x.67, and 
98x70 ; set (3), .90x.05, .90x.04, and.89x.65, 
set (4), .90x.65, .87x.6.5, and .90x.63 ; set 
(5), 1.03X.63, .95X.62, and .94x,65. A set 
of three which I sent T. G. Gentry and 
which he figures in Part XXV of his work 
on Nests and Eggs,* gives the following 
measurements as determined Iw him : 
.94x.69, .94x68, and .93x.68. The average 
of the first fifteen is found to be .923x.646 ; 
or of the eighteen, .925x.652. Baird, 
Brewer, and Ridgway’s North American 
birds gives .90x.60, being smaller than any 
one obtained by me. It is not stated where 
this egg was obtained, yet I presume it is 
either a Fort i\Iojave or an Arizona egg. If 
so, its small size when compared with more 
northern sjiecimens confirms Capt. Ben- 
dire’s conjecture that, when the usual set 
of eggs is fewer in the Southern than in 
tlie Northern 2 )ortion of any species’ breed¬ 
ing range, the eggs are also smaller. May 
it not be true that the individuals of any 
given species which go farthest North to 
breed, average a trifle larger and more ro¬ 
bust than the weaker brothers and sisters 
that stay at home ? It seems evident that 
those individuals which put the greatest 
number of miles between their Winter 
home and their breeding ground, must nec¬ 
essarily be the stronger ones ; the fatigues 
of tr.ivel. the changes of climate, and other 
modifying influences demanding and de¬ 
veloping a hanlier variety. And may not 
the larger size of the Northern egg jiermit 
a more j)rolonged embryotic development, 
resulting iu a chick of greater size and 
greater strength,—one better able to coi)e 
with its less favorable environment? I sug¬ 
gest this merely as a possible, and what 
appears to me a reasonable, solution of the 
question. 
R(>garding the singing abilities of the 
• IlliistrntionB of Xi-«tn and E(;c» of Kirdu of the- Cnitrd 
Stntei*, with Text; Ky Thoa. (J. (ientry. Philadelphia: J. 
A. Wai'eiiM'ller, Publihlior. 
