Nestling House Sparrows Research Articles

Nesting Activity of the House Sparrow in Hale County, Texas, During 1968

Nestling House Sparrows, Passer domesticus, are involved in the amplification of western encephalitis (WE) virus activity in Hale County, Texas, during the epidemic season (Hayes et al., 1961 Holden et al, 1973a). Experimental studies (Holden et al., 1973b) have shown that nestlings of this species are admirably suited for this role since they may circulate virus in the bloodstream for several days at concentrations sufficient for infecting vector mosquitoes. Information on the nesting activity and reproductive capacity of the House Sparrow in Hale County is requisite to an understanding of the seasonal dynamics of WE virus activity in the area; therefore, the present study was undertaken.

Effects of ultra-low volume applications of malathion in Hale County, Texas. I. Western encephalitis virus activity in treated and untreated towns.

Ultra-low volume (ULV) aerial applications of technical malathion at the rate of 214 g/ha (3 oz per acre) were applied routinely in 3 Hale County, Texas towns (Plainview, Abernathy, Hale Center) to reduce arbovirus transmission by mosquitoes during the summer of 1967. One untreated town, Petersburg, and 3 rural premises sites were selected for comparison. Used to evaluate the effectiveness of treatment were vector population indices before and after treatment, western encephalitis (WE) virus infection rates in mosquitoes and nestling house sparrows, WE antibody conversion rates in sentinel chicken flocks, and subclinical infection rates in school children. A significant reduction in the Culex tarsalis Coq. population level was evident only during the 48 hr immediately following treatment. Infiltration of adult mosquitoes from outside the treated areas was postulated to account for this rapid posttreatment population build-up. Seasonal WE virus infection rates in mosquitoes collected in treated and untreated towns did not differ significantly. Infiltration of infected adults into the treated areas may have contributed to the uniform infection rates. The WE virus infection rate was significantly higher in nestling house sparrows from untreated Petersburg as compared to Plainview and Hale Center, but not to Abernathy. Sparrow infection rates also were significantly lower at untreated rural sites as compared to Petersburg; therefore, factors other than ULV treatment must have been operative in keeping the infection rates at a low level. The WE antibody conversion rate in sentinel chicken flocks was significantly lower in Plainview than in Petersburg; however, observed differences in conversion rates between Petersburg and the 2 other treated towns and 3 rural sites were not significant. There was no confirmed human case of arboviral encephalitis in Hale County during 1967; however, few human cases were reported elsewhere in Texas or other parts of the United States during the year. The effectiveness of the ULV treatments in reducing the number of sub-clinical human infections was suggested, but the data were not conclusive. In order to control C. tarsalis in Hale County towns sufficiently to reduce WE virus activity, it was concluded that it would be necessary to make barrier treatments around the populated areas to prevent infiltration of infected mosquitoes.

FOOD, FEEDING RATES AND BODY TEMPERATURE IN THE NESTLING HOUSE SPARROW PASSER DOMESTICUS AT OXFORD

SummaryDiet, feeding frequency and body temperatures were studied in nestling House Sparrows at Oxford. In the diet, studied principally from crop contents, dipterous flies, caterpillars and aphids were most prominent in early May, early June and July respectively, while bread and dry grain, apparently less suitable foods, were more evenly distributed throughout the breeding season but apparently acquired an importance when insect foods were scarce.Adult House Sparrows increased the frequency of their feeding visits to the nestlings proportionately with brood‐size for broods of 1–3, but for larger broods the feeding frequency did not increase. This abruptly achieved upper limit presumably gave rise to inadequate feeding of the larger broods (including the principal brood‐size). The male's share of the visits decreased markedly in the later stages of the nestling period, corresponding to his initiation of a display directed at the female. His displaying at this stage probably allows the female to begin a further clutch soon after the previous nesting has finished.Nestlings were unable to maintain a steady body temperature above the ambient air temperature outside the nest before nestling day 10½. Maintenance of a steady body temperature depends on the nestling's feather covering, which is effectively complete at 9½ days. Before this, temperature control is possible within a limited range of ambient temperatures.

Ecology of arboviruses in Hale County, Texas, during 1965.

Summary A study was conducted in Hale County, Texas, during 1965 to obtain data on the arboviruses, arthropod vectors, and their reservoir hosts. Eleven cases in man of western encephalitis and four cases of St. Louis encephalitis were confirmed among 46 suspected cases reported by physicians from the Hale County area. A total of 128 virus isolations was obtained from Culex tarsalis; of these 81 were WE virus and four were SLE. There also were 37 isolations of Hart Park virus and six isolations of Turlock virus from C. tarsalis. Weekly transection counts of adult wild birds revealed that House Sparrows constituted 71% of the bird population—213 blood samples were obtained from nestling House Sparrows, and 51 arbovirus isolations were obtained. Thirty-eight of these were WE, seven were SLE, four were Turlock, and two were Hart Park virus. Ten virus isolations were made from 572 specimens of mammal blood; nine were WE, and one was Turlock. The data obtained on C. tarsalis seasonal populations and on the correlation between WE virus infection rates among C. tarsalis and P. domesticus nestlings provided new insight regarding the basic involvement of these nestling birds in the WE virus amplification cycle in this study area. Except for the index case in man, WE virus activity detected among sentinel chickens, wild mammals, and man commenced after that in C. tarsalis and P. domesticus. The data obtained in these studies further substantiate the fact that Hale County, Texas, is an area of hyperendemic arbovirus activity.