Necedah National Wildlife Refuge Whooping Crane Forced Renesting to Prevent Population Extinction
This is a notice of intent to award a single source cooperative agreement to the University of Wisconsin Stevens Point under justification 505DM 2.14B 4. This project was developed in conjunction with faculty at UWSP. The college of Natural Resources faculty at UWSP have expertise with the ecological principles of the USFWS along with analytical techniques necessary to complete the project. The university's proximity to the refuge and nesting areas also gives a unique qualification to nesting sites and observation times. After 13 years of releases of captive reared whooping cranes in the eastern United States, the eastern migratory population is estimated at less than 100 birds and is not self sustaining. The vast majority of adult birds nest on federally owned lands on or around Necedah NWR near where they were initially reared and released. However, the population is not self sustaining because hatching and fledging rates are near zero. This is because, since 2005 when adult whooping cranes first began nesting, most pairs have abandoned their nests and only a small number renest. Based on study results and field observations, the leads for this proposed project, with input from the Whooping Crane Eastern Partnership Research and Science Team, have determined that forced renesting should be implemented in an attempt to improve fledging success. Timing of renesting to coincide with reduced black fly numbers should increase the cranes reproductive success. Forced renesting has been successfully used to manage the endangered Mississippi sandhill crane for a number of years. Renesting rates up to 84 percent have been seen in this population. Improving the fledging rate is an integral component of establishing a second migratory population of whooping cranes, which is Object 1 of the downlisting recovery objectives identified in the 2007 International Whooping Crane Recovery Plan. Managing to improve reproductive success also supports goals and objectives in the Necedah National Wildlife Refuge Comprehensive Conservation Plan to provide a federal leadership role in conservation and recovery of federally listed species and more specifically the objective of providing support to the Whooping Crane Reintroduction program. The proposed project also addresses, with proven techniques, challenges facing this population outlined in the Wisconsin Whooping Crane Management Plan. Additionally, increasing whooping crane nesting success in the Necedah area was identified as a strategy in the Whooping Crane Eastern Partnership Five Year Strategic Plan. This project will continue for no more than 3 years. The program's field work will be to locate whooping crane nests by ground searching and visually monitoring within Necedah NWR and Meadow Valley Flowage Wildlife Management Area. Once nest s are located, they will be monitored by field staff twice daily by directly observing the nest via spotting scope from a sufficient distance to minimize disturbance (typically greater than 100 meters) for a minimum of 30 minutes or until both members of the pair can be identified via colored leg bands or VHF radio signals. We will attempt to visit each nest between 5 and 10 days after the start of incubation. Prior to black fly emergence eggs will be removed from nests to encourage renesting. Timing of egg removal will be based on results of ongoing black fly monitoring to estimate time of emergence. Eggs will be stored temporarily in a GQF digitally controlled incubator at Necedah NWR pending delivery to a captive rearing facility. While visiting nest, a Reconyx PC900 camera will be installed approximately 10 m from the nest and programmed to take 1 photo every 5 minutes throughout the nesting period. Because forced renesting has never been applied to whooping cranes, we will not use this management technique on all nests, instead we will manage half the nests and use the other nests as controls. The target population will be all pairs of whooping cranes nesting on Necedah NWR and the adjacent Meadow Valley State Wildlife Area. Management activities will take place within the defined boundary of Necedah's units in Juneau and Monroe counties, Wisconsin and within Mead Valley, which is a Coordination Area administered by the Wisconsin Department of Natural Resources through an agreement with the FWS. The success of this management technique over the next 3 years will dictate whether it is necessary to continue or not. Additional monitoring information is described under Methods and in the attached monitoring plan. After the completion of each nesting attempt, all nest monitoring images will be retrieved and reviewed as part of a University of Wisconsin Stevens Point graduate research project. For nesting attempts that yielded colts, hatching and nest departure dates will be determined. For unsuccessful nesting attempts, the date, and to the extent possible, cause of nest failure will be determined. Activities exhibited at the nest will be quantified for all camera equipped nests. Each photo will be categorized into nest specific activities (i.e .incubation, egg tending, standing, absent, incubation switch) and bird behaviors (preening, bill flick, head rub, head tucked). To confirm the effectiveness of the treatment, we will fit logistic regression models of the probability of renesting, given the first nesting attempt fails (a binomial response), as a function of the first nest failure date, growing degree day of the first nest initiation, length of first nest incubation and whether the nest was on the control or treatment group. Similar Model based approaches will be used to evaluate the impact of treatment effective on reproductive success. Hatching success rates will be modelled as a function of female age, prior hatching success of the pair, average exhibition of comfort behaviors during the incubation and treatment. Fledging success will be modelled as a function of female age, duration of pair bond, prior fledging success of the pair, and whether the pair was in the treatment or control group. Nests will be considered active when (a) eggs are seen or (b) behavior indicative of egg presence has been observed (i.e. egg rolling, incubation postures on two or more consecutive days). Nests will be enumerated in the order they are determined active. Whether the first nest will be a control or treatment nest will be determined by the toss of a coin, and determination will alternate between treatment and control for all subsequent nests. Thus the size of each group will be roughly equal and will be determined by the total number of nests located. On average, 21 initial nests were found between 2011 and 2013 within Necedah and Mead Valley. Therefore the anticipated size of each group will be eight to ten nests. After a pair's nesting attempt has failed (either natural failure in the control group pairs or forced nest failure in the treatment group pairs), staff will locate the pair and observe for one, randomly assigned, 30 minute observation session daily for 3 weeks. During each observation session instantaneous behavior sampling will occur at 30 second intervals specifically recording the occurrence of pair bond and breeding behavior (unison calling, copulation, nest building, etc.). All renest attempts will be treated similarly to the initial nest attempts in the control group. Specifically, nests will be visited within five to 10 days to install a camera. All camera equipped nests will be monitored by staff three times weekly until the completion of the nesting attempt. In a similar manner, colt survival will be monitored via direct observation at least three times a week until 90 days post hatch.
Office: U.S. FISH AND WILDLIFE SERVICE
brad_strobel@fws.gov
