Gunnison sage-grouse (Centrocercus minimus) (GUSG) is a species of concern in Colorado. Two conservation issues addressed in the Gunnison Sage-grouse Rangewide Plan (RCP) are the population persistence of GUSG (especially the small populations) and the relatively low genetic diversity among GUSG. Augmenting GUSG populations is a potentially useful management tool to address these conservation concerns. Five alternative techniques to transplanting juvenile or adult individuals are discussed in the RCP, including use of captive-reared GUSG. Researchers at the U.S.D.A. National Wildlife Research Center (NWRC) in Fort Collins, CO were able to maintain 18 yearling greater sage-grouse (C. urophasianus) (GRSG) in captivity for 8 months. Recent Colorado Division of Wildlife (CDOW) research on GRSG has evaluated different aspects of captive-rearing techniques (see more information at
Greater Sage-Grouse). Information from this research will be used to investigate techniques for the captive-rearing of GUSG.
The segment objectives for this project are to: 1) collect 40 GUSG eggs, 2) artificially incubate and hatch eggs, and 3) develop husbandry techniques for maintaining GUSG in captivity. Female GUSG were captured using spot-lighting techniques. Females were radio-marked to assist in locating nests. Eggs were collected from laying and incubating females. Forty eggs were collected from 6 females. Two eggs were collected during laying from one female and 38 were collected from 5 incubating females. Eggs were transported from the Gunnison Basin to Fort Collins and placed in an incubator until an internal pip was observed and then moved to a hatcher. Hatching success was 90% (36/40). Hatching began on 19 May and continued through 27 May. After hatching, chicks were weighed, banded, and fed an invertebrate dominated diet. Initial post-hatch survival (up to 3 days) 
was excellent resulting in 32 healthy chicks. At approximately 4 – 5 days of age bacterial infections occurred resulting in the death of 11 chicks. An additional 6 chicks died due to unknown causes (likely brooding substrate). Test results indicate that E. coli was the primary cause of the initial mortalities and the likely source was a top soil substrate purchased and used for a brood-rearing substrate. The additional 6 mortalities were possibly due to a wood chip substrate. Throughout the process CDOW and Colorado State University (CSU) veterinarians as well as Denver Zoo staff were consulted, provided advice,and prescribed medications. Chick broods were initially isolated in an attempt to control the unknown cause of death. As of 1 June, 15 chicks survived and ranged from 6 – 13 days of age. The chicks were moved to the NWRC facility on 5 June 2009 to a small pen within the aviary.
Due to the presence of West Nile Virus (WnV), since 1 July, grouse have been housed in a smaller area within the aviary that is covered by mosquito netting. Additional efforts to protect the grouse from WnV include, treating standing water in the area with Bacillus thuringinensis israeliensis (BTI) and the purchase of a mosquito trap that collects mosquitoes. Grouse are fed repeatedly throughout the day. Their diet consists of crickets, mealworms, superworms, waxworms, and game bird chow. Wild forbs are collected in the vicinity, presented to the grouse and are actively consumed. Dandelions are preferentially selected. Big sagebrush has been collected and planted in the aviary. Over the last month, consumption of sagebrush has increased.
Fifteen grouse were transported from the CDOW facility and currently 11 survive. One grouse died of unknown causes, one died of an injuries inflicted while flying in the aviary, and two died of selenium/vitamin E deficiencies. Vitamin supplemented water is provided and blood was collected from 6 GUSG to evaluate selenium/vitamin E levels. Blood results indicate that selenium levels are normal but vitamin E results are pending.
As of 1 September 2009, 11 grouse (3 males and 8 females) remain in captivity. Grouse were weighed on 31 August. Male grouse weighed 1,215 – 1,431 g and females weighed 757 – 938 g.
CDOW researchers will initiate the capture of 2-4 wild adult males and 3-5 wild adult females in mid-September. Grouse will be transported to Fort Collins and housed in a separate aviary at the NWRC. Husbandry techniques for fall and winter will be developed for wild and captive-reared grouse.
Period Covered: March 1, 2009 – September 1, 2009
PROJECT PERSONNEL:
Alan B. Franklin, Ph.D., NWRC/APHIS Fort Collins, CO
John V. Azua, Jr. Curator of Birds, Denver Zoo Denver, CO
Jenny Snyder CDOW Fort Collins, CO
Chris Yarbrough CDOW Fort Collins, CO
Claudia Camera CDOW Fort Collins, CO
All information in this report is preliminary and subject to further evaluation. Information MAY NOT BE PUBLISHED OR QUOTED without permission of the author. Manipulation of these data beyond that contained in this report is discouraged.
Demography and Dispersal
Principal Investigator: Michael L. Phillips
The U.S. Fish and Wildlife Service (USFWS) has determined that the Gunnison sage-grouse (
Centrocercus minimus) is a candidate species for listing as threatened or endangered under the Endangered Species Act. Seven Gunnison sage-grouse (GUSG) populations distributed across southwestern Colorado and southeastern Utah are described in the GUSG Rangewide Conservation Plan (see link to the Plan below). GUSG depend on sagebrush throughout much their life. The loss and fragmentation of sagebrush habitat may have important impacts on the long-term viability of GUSG populations, but the ecological mechanisms of these impacts are unknown. Our ability to conserve GUSG will depend on our ability to restore and protect a biologically relevant mosaic of habitats in a human-dominated landscape.
Three key assumptions made by biologists about the spatial ecology and population viability of a given species are: 1) demographic rates have significant influence on population persistence, 2) variation in demographic rates (due to environmental and demographic stochasticity) has a greater impact on small than large populations by significantly reducing persistence time, and 3) spatial variation in demographic rates and the ability to disperse can have a significant impact on species persistence time. The seven GUSG populations are likely to have different rates of demography and dispersal, as well as significant spatial and temporal variation (within and between populations). The effects of demographic stochasticity are likely to have a greater effect on persistence time in the smaller GUSG populations than in larger populations.
Population viability analysis (PVA) and spatially explicit population models (SEPM) are 2 analytical tools increasingly used by biologists to evaluate the relative effects of dispersal, demographic rates and changing landscape structure on the viability of small and declining species. PVA is a modeling approach to estimate the persistence time of a given species. SEP models evaluate the localized effects of landscape patterns on species distribution, abundance and population dynamics. SEP models are particularly useful for developing and evaluating alternative management strategies.
Information on the demographics and movement patterns of GUSG is necessary before constructing useful PVA and SEP models. The CDOW has conducted research to evaluate seasonal use patterns of GUSG, but we still lack detailed information on demographics and dispersal patterns within and among populations - particularly, estimates of spatial and temporal variation.
Therefore, the objectives of this research projects are: 1) to acquire estimates of demographic rates with the appropriate estimates of temporal and spatial variation, 2) to record movement patterns, habitat use and dispersal capabilities of GUSG, 3) to continue the analysis of genetic diversity to improve the accuracy of estimates and to re-evaluate intra- and inter-population variability, 4) to use the above estimates to update and refine a PVA model and to develop a SEP model specific to GUSG and GUSG landscapes, 5) to contrast the demography, habitat use and dispersal patterns in a large population (the Gunnison Basin) with the smaller populations, and 6) to use estimates of demographic rates and model output to develop and evaluate the projected consequences of alternative management plans.
We will use radiotelemetry to track GUSG movements, and to estimate nest success and survival rates of juvenile and adult GUSG. Movement patterns, habitat use and dispersal capability will be analyzed using a GIS.
The 2005 field season was a pilot study to collect preliminary data and to evaluate alternative study protocols. I expect to collect an additional 3 years of data and to complete the SEP model and update the PVA model by 2010.
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