Friday's Findings - March 19 2021

Release Date:

Impacts of translocation on the cooperatively breeding Florida scrub-jay in Ocala National Forest 

Date: March 19, 2021 from 2-2:30 p.m. eastern time

Speakers: Alexis Cardas, Graduate Research Assistant, University of Florida, USGS Florida Cooperative Fish and Wildlife Research Unit 

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Conference ID: 313 141 711#

Effects of Translocation on the Florida Scrub Jay in Ocala National Forest

(Credit: Alexis Cardas, USGS Florida Cooperative Fish and Wildlife Research Unit. Public domain.)

Background: Translocation has been considered as a conservation tool to increase the population of threatened and endangered species, especially in areas that have been recently restored, and where small, isolated populations reside and are unlikely to increase naturally through dispersal.  Most translocation research has focused on the success at recipient sites, while the impacts associated with the donor population have not been rigorously monitored.  Ocala National Forest is home to the largest remaining population of Federally Threatened Florida scrub-jays.  As the goal of any translocation is to have a positive impact on the species population, it is imperative that costs to the donor population are minimized to the greatest extent possible.  I studied nesting success and productivity at donor sites to assess the impact of translocation.  Our goal was to determine whether the removal of helpers from family groups of Florida scrub-jays is a viable option for future translocations. We removed a subset of helpers from family groups for translocation January-July of 2018 and 2019.  We monitored three categories of family groups: (1) no helpers (n=59), (2) helpers (n=34), (3) helpers removed (n=10).  We recorded nest success, mass of nestlings at age day 11, and time spent provisioning (recorded by nest cameras).  Overall, productivity and nestling weights were higher in 2018 than 2019 but we found no significant difference in nestling mass between group categories (no helpers and helpers present).  The best-supported model in predicting the daily survival rate of Florida scrub-jay nests included the additive effects of linear date within breeding season and year.  We found little support for group size (helper, no helper) as a factor to be predictive of daily survival rate.  Our results suggest that the presence of non-breeding helpers has less of an effect on nestling mass, productivity, and nest success than the factors of year and linear date within season.  Our data suggests that removing helpers is a viable option for future translocation efforts of Florida scrub-jays.   In addition to concurrent research conducted at the recipient sites, this will be an important first step towards the initiation of a statewide translocation protocol for Florida scrub-jays.