Genetic variation, population substructure and sex ratio of the Florida scrub-jay, Aphelocoma coerulescens coerulescens

The Florida scrub jay, an endemic bird species in Florida, was listed as threatened in 1988. Though protected, the populations continued decline is likely caused by habitat degradation and fragmentation. Long term demographic, life history, and population viability studies have been undertaken, however none have contained a genetic component or established sex ratios. Objectives for this study are threefold and incorporated scrub jays from nine areas in Brevard County, FL. Scrub jays were trapped, banded and blood sampled between August, 2004 and June 2007. DNA was extracted for use in molecular sexing and determining population substructure using microsatellites. The sex ratio of each bird was identified using P2-P8 primers of the CHD gene. Eight morphological characteristics were measured in the field and evaluated using a discriminant function analysis to sex these birds. Ten microsatellites were used to assess the levels of heterozygosity, test for deviation from Hardy-Weinberg Equilibrium, and F-statistics were used to determine levels of inbreeding and diversity. All tests were correlated to habitat quality to determine if habitat had any effect on sex ratio or genetic makeup. The sex ratio was determined to be 1:1 (p<0.05), was not affected by habitat quality, and appeared that it was not adaptive. Eight morphological characteristics provided 88% accuracy in determining sex from field data while 4 characteristics lowered the accuracy to 80%. Observed heterozygosity for 9 metapopulations indicated an excess of homozygous individuals at most areas. Heterozygosity decreased with decreasing habitat quality. Deviation from Hardy-Weinberg Equilibrium was significant at 9 of 10 loci in tertiary habitat, while only 6 were affected in primary habitats. F(is)/Rho(is) and F(st)/Rho(st) indicated inbreeding was occurring and there was limited gene flow. There is clear indication that the Florida scrub jay has experienced loss of genetic heterozygosity and shows some level of inbreeding. This information could be vital to future management decisions, possible translocation studies, or habitat restoration projects.