PARENT SESSION
Oral Session #36: Conservation of aquatic systems: Ecology and ecotoxicology. Presiding: R. Lathrop.
Tuesday, August 7, 2001. 1:00 PM to 5:15 PM. Hall of Ideas H.
Growth patterns in common loon chicks as related to mercury (Hg) exposure and adult care.
Fevold, Brick1, Meyer, Michael2, Temple, Stanley1, 1 2
ABSTRACT- Chronic exposure to dietary mercury has produced anorexia in mink, otter, and harp seals, as well as ataxia and behavioral aberrations in mallards and other species. Previous research on common loons (Gavia immer) found an association between elevated blood-mercury (Hg) levels and reduced nesting success and chick fledging rates. A field study was implemented during years 1999 and 2000 in north-central Wisconsin to determine whether this reduced reproductive performance can be explained by similar physiological and/or behavioral aberrations. Focal-animal observations were conducted on 37 adult loon pairs and 46 chicks. Observations were selected in a stratified-random manner, and were performed every 2-3 days. Each observation lasted 2 hours and consisted of continuous sample recording. In addition, morphological measurements were conducted on chicks from hatch to 35 or 40 (year 2000) days. Chick growth measurements were conducted at approximately age 3, 15, 35, and 40 days to develop a growth curve. Recapturing chicks older than 40 days has diminished success. Blood samples were also collected and shipped to EnChem Inc. for analysis of total mercury. Preliminary analysis of 1999 growth data suggest no significant association between differences in chick growth and blood mercury exposure. This paper will present results from analysis of morphometric data with reference to parental care from combined years of 1999 and 2000
KEY WORDS: avian behavior, morphometrics, mercury, common loon