Production of Mallards on Irrigated Land in the Sacramento Valley, California

Abstract

The primary aim of the investigation here reported was to measure the production of mallards on the Conaway ranch, an area of irrigated farm land in the Sacramento Valley of California. Production was calculated from census figures of (1) the breeding population at the onset of nesting, and (2) the total mallard population (young and surviving adults) at the period in midsummer when the young were beginning to fly. A secondary objective was to study the ecology of nesting in order to understand the limitations in production. The various phases of the study are recorded in the chronological order in which they were completed, with discussion of total production deferred to the end, following the postbreeding