Pre-incubation movements of female wild turkeys relative to nest initiation in South Dakota

Abstract

Nests of radiotransmittered wild turkeys (Meleagris gallopavo) that are destroyed or abandoned prior to incubation are particularly difficult to locate. As a result researchers often report only incubated nests or estimate numbers of nests attempted by localization of movement or other behavioral changes without quantification. We used radiotelemetry to obtain movement data on female wild turkeys during the nesting season (1 Apr‐30 Jun) in South Dakota. We collected prelaying (1 April until 14 days before the female initiated incubation) and laying (<14 days before incubation) movement distances from 160 adult female wild turkeys [75 eastern (M. g. silvestris), 19 Rio Grande (M. g. intermedia), and 66 Merriam's (M. g. merriami) wild turkeys]. Our objectives were to quantify the relationship between movement behavior and nesting attempts to allow more accurate determination of initiation of nesting for calculation of nest rates, nesting success, and renesting rates. Daily movements of females decreased abruptly when they transitioned from prelaying to laying behaviors. Movements of females that were less than 364.9 m for eastern turkeys, 115.0 m for Rio Grande turkeys, and 331.0 m for Merriam's turkeys were indicative of nest initiation. Changes in movements of females can identify nesting wild turkeys and can be used post hoc to identify nests that were abandoned or destroyed prior to incubation if sufficient locations are collected. Following our analysis, we estimated that females had an additional 46 nests (eastern = 15, Rio Grande = 7, and Merriam's = 24), which we used in estimating reproduction parameters. Quantitative comparisons of movements between prelaying and laying confirmed a behavioral change of localized movements concurrent with nest initiation in wild turkey females.

Merriam's Turkey Nest Survival and Factors Affecting Nest Predation by Mammals

“…Laying-period nest survival was 1.0 based on nests we found during this study; however, there was some nest predation occurring during the laying period based on movements examined post hoc (Lehman et al 2005). We estimated that 15% of nests were lost during the laying period.…”

“…Nesting rate for yearling females was 50% (5 of 10 for pooled yr) and annual nest success for yearlings was 83% (5 of 6 were successful for pooled yr). Renest rates for adults did not differ among (Lehman et al 2005). d Proportion of F alive on 1 Apr that attempted to nest (Cowardin et al 1985).…”

“…f Proportion of all observed nests in which !1 egg hatched (Cowardin et al 1985). g Adjusted nest success (includes additional nests that we did not observe directly in the field but were based on localized movements post hoc; Lehman et al 2005). years (v 2 ¼ 1.02, df ¼ 2, P ¼ 0.60) and averaged 75% (SE ¼ 6.3; Table 1).…”

“…We defined nesting rate as the proportion of females alive on 1 April that attempted to nest, and nest success as the proportion of all known nests in which !1 egg hatched (Cowardin et al 1985). Adjusted nest success, or an estimate of annual nest success included additional nests lost during the laying period that we did not observe directly in the field but were based on localized movements post hoc (Lehman et al 2005). We defined female success as the proportion of females that successfully hatched !1 poult and renest rate as the proportion of females unsuccessful on their first nesting attempt that attempted another nest (Cowardin et al 1985).…”

Winter and summer weather modulate the demography of wild turkeys at the northern edge of the species distribution

“…As a consequence, reported nesting success estimates are often inlated while nesting attempts are often under-estimated. However, it is possible to quantify nesting attempts during incubation by analyzing changes in movements of hens if suicient locations are collected (Lehman et al 2005). During our study, we had enough locations of hens equipped with Argos-GPS transmitters to evaluate nesting during the pre-incubation period.…”