This Turkey Tuesday is about the groups of older poults we’re hopefully seeing across our landscapes. Once poults reach 2 weeks of age, their survival increases dramatically as they begin flying to avoid predation and roosting in vegetation above ground. As poults age, you can begin to identify them as males or females based on feather characters and leg length. But within groups of these older poults, logically you’d assume that the sex ratio would be split 50:50, right? Well, increasing evidence across various sites suggests that the sex ratio in juvenile birds in fall flocks is skewed – often quite a bit – towards males. Why? First, research in Texas showed that clutches of eggs within a nest were already skewed towards males – ~55:45. Second, research on various birds has shown that incubation temperature can alter sex ratios, in that female embryos are more likely to die at cooler temperatures than males. Other work has shown that clutches in some birds will be skewed towards males when the nesting female is nutritionally stressed. Third, once hatched, male poults grow faster relative to females, and male poults are more resilient during inclement weather conditions. Fourth, male poults within brood flocks are typically more aggressive than females, which may offer them better access to foraging resources when they’re limited. Looking back at data collected back in the 1980s and 90s, it was common for 35-40% of female turkeys captured in fall and winter flocks to be juveniles. Across many sites we work on, those numbers range from 5-25% in any given year, and hover consistently around 15%. The take home is, we know that we’re not producing as many young turkeys as we used to, but emerging evidence suggests that other factors may be at play that are influencing the composition of the flocks we are producing. Ongoing research will hopefully provide some answers as to why.
Photo by Eric Orlando.
