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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 borde,'ed by patch- es of weeds or brush. 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 cen?ers of the state. At my orange grove in Covina, fumigating was begun November 25, ?9 II, and most of the trees were treated, taking, in all, four nights. During thc first night two hundred large trees were finished, and the next morning I counted under them the following dead birds: 37 House Finches (Carpodacus mexicanus frontalis) 24 Goldfinches (Astragalinus tristis salicamans and A. psaltria hcsperophilus) 11 Audubon Warblers (Dendroica auduboni auduboni) 7 Gambel Sparrows (Zonotrichia leucophrys gainbell) 4 San Diego Song Sparrows (Melospiza mclodia cooperi) 4 Western Chipping Sparrows (Spizella passerina ari, onae) 3 Hermit Thrushes (Hylocichla guttata nanus) 1 Western Mourning Dove (Zenaidura macroura 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 gTonnd to the birds. Subsequent to the above date I have found, besides the forms already enumerated, a few Western Mockingbirds (Mimus polyglottos leucopterus), California Thrashers (Toxos- roma redivivum redivivum), a Dusky Warbler (Vermivora celata 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- ty.r ca!ifornica 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 2oo,- ooo acres of bearing citrus groves in the state, planted with over eighty trees to the acre. These ?,6oo,ooo trees are fumigated on an average every two years, which would give a total of 36o,ooo 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