Seasonal Insect Food of the Western Chipping Sparrow

Abstract

The following study deals with the -recognizable insect food contained in 283 stomachs of the western chipping sparrow, Spizella passerina arizonae Coues, collected throughout the state of Utah during the nine years from 1934 to 1942, inclusive. The majority of the birds were collected in areas of Russianthistle or other host plants of the beetleafhopper, Eutettix tenellus (Baker), during late summer and fall, when this insect pest usually is most abundant. The other collections were made throughout the season in agricultural and range areas. The birds were collected as opportunity permitted; this resulted in the collection of: 3 stomachs in April, 7 in May, 10 in June, 14 in July, 45 in August, 174 in September, and 30 in October. Injurious species of insects contained in the 20 western chipping sparrow stomachs collected from April through June included: seven nymphal and one adult grasshopper; 34 false chinch bugs, Nysius ericae (Sch.), 5 Miridae, 2 being Lygus hesperus Knt. and 1 L. elisus Van D.; 27 leafhoppers, 13 being adult and 1 nymphal Eutettix tenellus; 1809 aphids, at least 1528 of these being pea aphids, Macrosiphum pisi (Kalt.), 125 M. coweni Hunter, 12 Aphis bonnevillensis KnIt. and 12 Epameibaphis atricornis G.-P.; the beetles included 13 alfalfa weevils, Phytonomus posticus (Gyl.), 5 pea weevils, Bruchus pisorum (L.), 1 rose snout beetle, Rhynchites bicolor Fabr., 1 Disoncha triangularis (Say) and other weevils and leaf beetles; approximately half of the lepidopterous larvae were cutworms, many of them being army cutworms and variegated cutworms, only 2 specimens being adult moths; 4 of the Diptera were larvae; 15 ants were contained in 5 stomachs. In addition were 13 spiders and mites, 62 seeds (including Russian-thistle and Atriplex) and plant fragments were present in three of the stomachs. Insect food contained in the 59 stomachs taken durintg July and August included: 10 adult and 5 nymphal grasshoppers, 1 -field cricket, 1 mantid and I Mormon cricket egg; 37 termites; 234 adult and 23 nymphal false chinch bugs, 9 Miridae included Lygus elisus and L. hesperus, 1 Sinea diadema (Fabr.), 1 Pentatomidae, 2 Scutelteridae, and also 6 Geocoris decoratus UhI. which big-eyed bug commonly feeds on the beet leafhopper, pea aphid and several other injurious small insects. The leafhoppers included 10 adult and 1 nymphal beet leafhopper contained in the 14 stomachs collected during July and 37 adults and 7 nymphs in the 45 stomachs taken during August; 3 Psyllidae, 2 Cercopidae, 2 Fulgoridae, 23 Coccidae, of the 1424 aphids found, 18 wAere recognizable as pea aphids, 1 Lachnus salignus (Gm.), 2 Myzus persicae (Sulz.), 2 Macrosiphum filifoliae G.-P., 6 Aphis cerasifoliae Fitch, 1 A. varn-