Effects of food supplementation on the nesting dynamics of wild northern bobwhite

30 January 2018

Buckley, Byron; Andes, Alica; Dabbert, Brad

Avian females with food limitation or are unable to meet nutritional requirements could result in negatively influenced egg size, nest initiation date, nesting season duration, and clutch size. Northern bobwhites Colinus virginianus serve as an adequate model species for supplemental feeding studies because of prolific nesting and re-nesting behavior. We monitored females on treatment and control units to determine if food supplementation influenced: 1) nest initiation, nesting duration, and nesting attempts, 2) nesting success, and 3) egg volume and clutch size. We radio-marked 196 female bobwhites during the breeding season of 2011 and 2012. Hens with access to supplemental feed produced 0.86 and 1.60 nest per hen while hens on control sites produced 0.15 and 0.81 nest per hen during the 2011 and 2012 nesting season, respectively. Average nest initiation varied slightly between treatment and control; though, average nesting season length was 16 and 31 days longer on treatment units. This benefit indicates females with access to food supplementation were in better physical condition compared to females on control units. However, nest success (β = -0.03, SE = 0.40), clutch size (t = -0.37; p = 0.70), and average intra-clutch egg volumes (β = -0.06, SE = 0.20) (t = 0.50; p = 0.61) were unaffected by food supplementation. Total net productivity estimates showed more chicks per hen were produced on treatment sites [Ṗ = 2.34, SE = 0.04 (2011); Ṗ = 5.75, SE = 0.12 (2012)] than control units [Ṗ = 0.61, SE = 0.001 (2011); Ṗ = 3.47, SE = 0.13 (2012)]. Our results suggest that bobwhites with access to supplemental feed broadcast into roadside vegetation throughout the breeding season can potentially increase nesting attempts which may result in increased production and offset population fluctuations due to drought conditions.