The breeding biology of the horned lark (Eremophila Alpestris Alpestris L.) at Cape St. Mary's, Newfoundland

Abstract

The breeding biology of the Horned Lark (Eremophila alpestris alpestris (L.)) was studied during the 1976 breeding season at Cape St. Mary’s, Newfoundland. -- The timing and function of ground singing, song-flights, and other vocalizations was discussed. Territorial behaviour was investigated, and territories were subsequently mapped to determine their size (2.313 - 5.125 ha, mean 3.542 ha). Male territorial hostilities and courtship behaviour were discussed. -- Nesting phenology was studied in detail. Nests were analyzed for position and structure; they tended to be protected on the windward side. Clutch sizes of early and late nests were compared (early 3.0, late 3.5, overall mean 3.31). Forty-seven nestlings were measured to calculate growth curves for weight and other body parameters. Breeding success, incidence of renesting, and the mean number of fledglings produced by each pair were calculated. Causes of egg and nestling loss were analyzed. About on-quarter of the breeding pairs raised two successful broods.