SPRING MIGRATION PATTERNS OF MALE RED-WINGED BLACKBIRDS (AGELAIUS-PHOENICEUS) FROM 2 MIGRATORY ROOSTS IN SOUTH-DAKOTA AND MINNESOTA

During March 1985 male red-winged blackbirds (Agelaius phoeniceus) wer e marked with aerially applied fluorescent-colored pigments at two mig ratory roost sites in southeastern South Dakota and western Minnesota to determine their dispersal to breeding areas. Postspray samples reve aled that approximately 54% (1.58 million) of the males present were m arked with at least one of four pigments used. During late spring, bre eding males were shot in 16 predetermined collecting areas in four N-c entral states in the United States and three central Canadian province s. Of 3289 males collected, 555 (16.9%) were marked with one or more p igments; 86.8% (482) of the marked birds were from the South Dakota ma rking site and 13.2% (73) from the Minnesota site. The 16 collecting a reas where male redwings were shot were grouped into six recovery regi ons for chi-square analysis. Results showed unequal proportions of mar ked breeding males among the recovery areas (P = <0.001). Temporal use of the South Dakota roost site by migrating males also affected breed ing male distribution (P = <0.001). Inadequate sample sizes precluded analysis of temporal distribution of marked birds from the Minnesota m arking site. Although marked redwings were dispersed over several thou sand square kilometers from South Dakota to Alberta, Canada, 76% of th e marked male redwings from South Dakota were concentrated in southern Saskatchewan and N-central North Dakota; 74% of the marked birds from Minnesota were concentrated more easterly in southern Manitoba, north eastern North Dakota and northwestern Minnesota. The N-northwestward d istances traveled by migrating male redwings from marking sites to bre eding areas was significantly different (P = 0.006) among groups marke d at different time intervals at each site. Distances traveled ranged from 856 km to 1093 km.