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.