Renesting and Second Nesting of Individually Marked Red-Winged Blackbirds

Abstract

The study was conducted on the Patuxent Wildlife Research Center, Laurel, Maryland, in habitats where the nesting population of Red-wings is large. The approximate nest density that prevails in this habitat is indicated by the results of an intensive search for nests in 1961, when 144 active nests were found in 150 acres of nesting habitat. More detailed nest studies were made in 1962: 26 nesting females were caught in nest traps and were individually marked with several layers of colored plastic tape wrapped around the tarsus of each leg. Previous testing of this type of color marker on captive and wild Red-wings had shown that such markers would remain for at least months. Birds also were banded with Fish and Wildlife Service numbered bands. Each nest was identified by a numbered white tag 1 1/2 x 3 placed several feet from the nest. Twenty of the marked birds were in three adjacent upland hayfields totaling about 20 acres, and 6 were in a marsh of about 19 acres. Seven of the females were subadults in plumage and 19 were adults.