Population Characteristics of American Woodcock Wintering in Texas

Despite recent stabilization in measured indices, American woodcock (Scolopax minor) populations have demonstrated long-term population declines since 1968 as measured by the Federal Singing-Ground and Wing-Collection surveys. We quantified long-trends in annual sex and age ratios, recruitment index, and changes in body mass of 3,022 woodcock harvested in eastern Texas during winters of 1977-78 through 2002-03. The mean juvenile:adult ratio was 0.58 and none of the annual values exceeded 1.0. This ratio declined significantly over time for females. The male:female ratio for all birds also declined from 1977 to 2002. The calculated recruitment index (number of harvested young/harvested female) of 1.03 for this population was nearly 50% lower than the published (1.9) Federal index for Texas from 1963-2005. There was a negative yearly trend in wintering body mass for adult males and adult females, with both groups experiencing a 3% decline. Within years, mean daily body mass of adult males declined from November through February, while mass for other age and sex classes increased or showed no trend. Adult males exhibited different patterns of within and among year changes in body condition compared to adult females, juvenile females, and juvenile males. The long-term declining trends in female age ratio, recruitment index, and adult body mass provide evidence that American woodcock are declining in eastern Texas. We recommend initiation of a coordinated national effort to identify specific mechanisms for American woodcock declines, and collection of more detailed population data on breeding, migrating, and wintering grounds.

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