High Male Incubation Good Sign for Fall Bobwhite Abundance

Quail chicks leaving nestThe quail hatch is shaping up to be a good one! Plenty of adult bobwhites and broods are being observed and reported across the Red Hills and Albany area quail properties, as well as our study sites on central Florida Ranches, the Carolinas and Alabama. Breeding season adult survival has been excellent in the Albany area, the Carolinas and central Florida, but average to slightly below average in the Red Hills region. On all of our study sites along the east Coast, we have been seeing average to above average production compared to our historical records. In the Albany area, nest production per capita is well above average, whereas brood production per capita is slightly below average, supposedly due to high attrition from snakes. On all of our other sites (in the Carolinas, central Florida and the Red Hills), nest and brood production has been about average at the mid-season point, but good breeding season survival on all sites, with the exception of our Red Hills study sites, affords a lot of opportunity for birds to re-nest and/or hatch second broods.

Despite average production, poorly timed rains resulted in high amounts of chick mortality in the Red Hills during the first (late May, early June) wave of hatches, but chick survival has dramatically improved since then. However, high snake activity has resulted in higher than usual chick mortality to snakes, compared to the past couple of years. The good news is that there still appears to be a lot of cotton rats out there to alleviate the pressure on the young quail chicks. In fact, on our Albany area study sites, we recorded an all-time high abundance of cotton rats during our early August sampling period.

Beyond chick survival and our typical per capita production tracking metrics (broods and nests produced per hen), male incubation rates are excellent so far at >27% for Tall Timbers and Dixie study sites which is already at our long-term average for the entire breeding season. Our recent research has shown that male incubation patterns are 2.5 times more predictive of population change than any other bobwhite demographic we monitor. As a result, when male incubation rates are above average, we are 78% more likely to observe a population increase, compared to years when male incubation rates are lower than 28%. During years when male incubation is higher than normal, overall production from hens can be biased low or underestimated, which appears to be the case this year. An even greater predictor of population growth is broods hatched by males. To date, the number of broods hatched by males is 0.16 for the breeding season. Our long-term data on Tall Timbers indicates that when broods produced per male is at or greater than 0.16, a population increase was observed nearly 88% of the time (see Figure 1). If this pattern is holds true for this year, we could see modest increases in fall bobwhite abundance.  Taken collectively, there is reason for optimism heading toward the breeding season finish line. A good late hatch will be the deciding factor for many as to whether population increases are observed this fall compared to last year.

Figure 1. Bobwhite density (and lambda – population growth rate) and reproduction of Northern Bobwhite at Tall Timbers from 2000 – 2019. Gray bars represent bobwhite density (birds per acre) and solid black line lambda; the dotted-black line represents successful male-incubated nests per radio-tagged male (broods per male), and the dashed-grey line represents successful female-incubated nests per radio-tagged female (broods per female).


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