Mar., 1914 
DESTRUCTION OF BIRDS BY FUMIGATION OF TREES 
55 
that habitually resort to it at night, for one that is surrounded by other groves 
or plowed ground would not prove as attractive as one that is bordered by patch- 
es of weeds or bru.sh. Also the bird mortality on a certain tract would vary 
greatly according to the time of the year when fumigation is undertaken. If 
during August, no dead Dwarf Hermit Thrushes, Gambel Sparrows nor Audu- 
bon Warblers would be found. Later in the season flocks of House Finches seem 
to frequent the groves more during the night, than in the early fall. 
'Conditions were observed only in my own and nearby groves, so my gen- 
eralities applying to supposedly similar conditions farther afield must not be tak- 
en for absolute proof. In this case, however, what holds good in one district 
must apply to a greater or less extent to all the citrus centers of the state. 
At my orange grove in Covina, fumigating was begun November 25, 1911. 
and most of the trees were treated, taking, in all, four nights. During the first 
night two hundred large trees were finished, and the next morning I counted 
under them the following dead birds : 
37 House Finches {Carpodacus inexicamts frontalis) 
24 Goldfinches (Astragalinns tristis salicamans and A. psaltria licspcropliilus) 
11 Audubon Warblers (Dendroica auduboni anduhoni) 
1 Gambel Sparrows {Zonotrichia leucophrys gambeli) 
4 San Diego Song Sparrows {Melospisa mclodia cooperi) 
4 Western Chipping Sparrows (Spisella passerina arizonae) 
3 Hermit Thrushes (Hylocichla guttata nanus) 
1 Western Mourning Dove (Zenaidura inacrGura marginella) 
1 Anthony Towhee (Pipilo crissalis senicula') 
This was the only time that I made a careful and accurate count (though I 
may have missed several), but there seemed to be slightly more birds then than 
on any other day that observations were made. Also my grove would probably 
give a greater count than the average, as on two sides it adjoins weedy land 
which proves a rather attractive feeding ground to the birds. Subsequent to the 
above date I have found, besides the forms already enumerated, a few Western 
Mockingbirds {Mimus polyglottos lencopterus) , California Thrashers (Toxos- 
toma rcdiviviun redivivum), a Dusky Warbler (Vennivora cclata sordida), and 
a partly decomposed hummingbird of some kind. Groves in other districts, as in 
the foothills or along the rivers, must have additional species roosting in them. 
A citrus tree and especially the orange, having rather dense foliage, presents a 
snug retreat, and it seems safe to say that practically all species would be found 
in them that habitually roost in the low trees of the districts in which the groves 
occur. From my own experience I am led to believe that Valley Quail {Lophor- 
tyx calif oruica vallicola), although they commonly pass the night in the groves, 
do not suffer to any extent by fumigation, for they take alarm very easily and 
are driven out of the trees at any hour by any suspicious activity near-by. 
Under two hundred trees I found ninety-two dead birds and there are 200,- 
000 acres of bearing citrus groves in the state, planted with over eighty trees to 
the acre. These 1,600,000 trees are fumigated on- an average every two years, 
which would give a total of 360,000 dead birds each year. As noted above, I be- 
lieve this estimate to be slightly in excess of the real number, but even if we take 
but a third of this amount we must consider that it takes place on an aggregate 
of one hundred and fifty-three square miles. This is a large mortality for so 
small an area every two years, or only half the area each year. 
Is there a remedy? The laborers employed by the fumigating companies 
are notoriously careless of the property on which they are working and I judge 
that very few of them would lift a hand in order to save the life of a bird. It 
