North Florida Sandhill Crane Populations

SANDHILL CRANES (Grus canadensis) occur regularly on several prairies, lake margins, and marshes in northern Florida, but to our knowledge no previous attempt has been made to determine the size, source, and subspecies of these populations.This paper reports recent data on migration time and routes and the nesting and wintering grounds of the Sandhill Crane populations in northern Florida.METHODS AND MATERIALS Between 1963 and 1971 we visited all localities in Florida north of Marion County and east of the Aucilla River (Figure 1) where Sandhill Cranes were known or believed to occur.From 1968 through 1971 these places were rechecked by airplane, surface vehicle, or on foot.We visited Pinhook Swamp (a part of the Okefenokee Swamp) only during 1963 and 1964 in connection with another study.We did not census west of the Aucilla River because cranes are rare there (Howell, 1932; Weston, 1965), nor did we survey the Florida peninsula south of Alachua County because the species nests so widely there that the land area to be searched would necessitate a study of greater scope than we were able to undertake.We obtained some unpublished information (H.M. Stevenson and R. L. Thompson, pers.comm.) on a small population in Liberty County near Sumatra.Capturing and marking.--In the winter of 1967-68, 24 cranes captured on Orange Grove Lake Prairie and 26 captured on Paynes Prairie were tagged with light green patagial tags (KnowIron et al., 1964), banded with size 8 or 9 standard U.S. Fish and Wildlife Service bands above the distal joint of the tibia, and released at the capture sites.In the winters of 1968-69 and 1969-70, 119 more cranes were banded and colormarked on Paynes Prairie, for a total of 169 wing-marked and banded for this study.Cranes were caught by a technique similar to that used to take wild Turkeys (Meleagrls gallopavo) (Williams, 1966).On prebaited sites they were fed whole yellow corn (maize) dampened and dusted with powdered alpha-chloralose at dosage rates between 0.35 and 1.50 g per standard cup of bait.The most effective dosage was 0.40 to 0.45 g of the drug per cup of corn.Narcotized cranes were held in large cardboard boxes or in burlap feed sacks with their legs securely taped together at the distal end of the tarsometatarsus.They were released at the capture sites after they recovered, usually the day after capture, but a few heavily drugged birds slept for 2 days.Sightings and recoveries of marked cranes.--Wealerted potential observers to watch for color-marked cranes and sent letters explaining the study to state and federal conservation agencies and private individuals in the eastern and midwestern United States and Canadian provinces where Sandhill Cranes were known (Walkinshaw, 1949) to nest or occur in migration.Reports of 160 sightings of marked cranes north of Florida have been received and four bands have been recovered as this is being written (April 1971).About 60 other cranes wearing bands on the lower tibia were reported in the same areas that colormarked birds were seen and probably also refer to our birds, but only reports of green color-marked cranes are used in this report (Tables 1 and 2).Four bands were recovered through the facilities of the Bird Banding Office, Bureau of Sport Fisheries and Wildlife.

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