16 
THE CONDOR 
Vol. XV 
but I did take down, after the builders had left, some of the nests from the cabin 
for examination and photography, and noted no parasites of any sort. 
Most animal parasites will not live for any length of time on any host other 
than the natural one, though some have several hosts, and a few seem quite in- 
different in such matters. What the case is with the swallow bed-bug I do not 
know. I would suggest to my readers that in such cases as may come to their 
notice they secure specimens of the bugs and submit them to an expert for identi- 
fication. Certainly the matter will bear further investigation. Incidentally I 
may remark that it is worth while to collect any parasites one may find on any 
animal and turn them over to some one interested in these things. I have made 
it a point lately to always have a few vials containing weak alcohol with me 
when collecting, and putting into them the parasites which often immediately 
show on a dead animal, with a label to show from what species they were taken. 
I must express my appreciation of Mr. Dawson's courtesy in writing me 
about the matter instead of correcting me in the Condor, which he would have 
been justified in doing under the circumstances as known to him. As it happens, in 
a way we were both right and both wrong, so we should both be satisfied. 
NOTES ON SOME FRESNO COUNTY BIRDS 
By JOHN G. TYLER 
Recurvirostra americana. Avocet. 
I N PURSUING ornithological studies the bird student is often led to wonder 
what strange economy of Nature causes certain species to choose an en- 
vironment that, from a human standpoint, would seem unsuited to a creature 
of gentle disposition and attractive plumage. 
Several miles southwest of Caruthers, Fresno County, California, are a 
number of shallow ponds of greater or less extent, according to the amount of 
winter rainfall, and all but two of them possessed of a freakish tendency to be- 
come entirely dry at times, only to fill up again without warning. Surrounded 
by salt-grass knolls, their borders entirely devoid of vegetation of any kind, these 
ponds are not the most picturesque places in the valley, especially in view of the 
fact that the water is alkaline and in summer often becomes stagnant. A more 
foul-smelling, unattractive place could hardly be found, yet these ponds are re- 
sorted to each spring by a company of Avocets that remains throughout the 
summer. It is evidently a matter of , choice rather than necessity with these 
handsome waders, too, for there are numerous overflowed pastures and per- 
manent ponds- in other parts of the valley, each of which claims its nesting colony 
of Stilts every spring; but while a few of the latter may ofttimes be found with 
their larger cousins, yet I have never found the Avocets elsewhere than in the 
immediate vicinity of the most sterile sinks. 
When the water in these ponds is subjected to the rays of the summer sun, 
a slimy, jelly-like substance appears around the edges and attracts myriads of 
flies, which often form an unbroken black band four feet or more in width and 
completely encircling the ponds. Is it not possible that these flies are one of the 
staple articles of food with the big waders? Possibly this is the solution of their 
attachment to these uninviting ponds. A similar assemblage of flies has been 
previouslv noted by Walter K. fiisher (Condor, iv, 1902, p. 9) occurring at 
Mono Lake. 
