FEASIBILITY ASSESSMENT FOR REINTRODUCING THE SLENDER-BILLED WHITE-BREASTED NUTHATCH TO SOUTH PUGET SOUND, WASHINGTON Prepared by: Gary L. Slater Bob Altman Ecostudies Institute American Bird Conservancy P.O. Box 703 311 NE Mistletoe Circle Mount Vernon, WA 98273 Corvallis, OR 97330 Prepared for: Pacific Coast Joint Venture U.S. Fish and Wildlife Service ACKNOWLEDGEMENTS 2 TABLE OF CONTENTS ACKNOWLEDGEMENTS............................................................................................................ 2 TABLE OF CONTENTS................................................................................................................ 3 LIST OF TABLES.......................................................................................................................... 4 LIST OF FIGURES ........................................................................................................................ 4 INTRODUCTION .......................................................................................................................... 5 PURPOSE....................................................................................................................................... 6 STATUS ......................................................................................................................................... 6 Conservation status ..................................................................................................................... 6 Systematics ................................................................................................................................. 7 Historic and current distribution ................................................................................................. 8 Changes in Population Status...................................................................................................... 9 Population Trends ..................................................................................................................... 10 LIFE HISTORY............................................................................................................................ 11 Habitat....................................................................................................................................... 11 Density and territory size.......................................................................................................... 12 Site fidelity................................................................................................................................ 13 Food habits and foraging .......................................................................................................... 14 Breeding biology and demography........................................................................................... 15 CAUSES OF EXTIRPATION...................................................................................................... 16 Habitat Loss and Degradation................................................................................................... 17 Cavity Availability.................................................................................................................... 18 Food Availability ...................................................................................................................... 20 Effects Associated With Small Populations ............................................................................. 21 Conclusions............................................................................................................................... 21 ADDRESSING THE CAUSES OF EXTIRPATION................................................................... 22 Oak Habitat Loss and Degradation........................................................................................... 22 Effects associated with small populations ................................................................................ 23 Conclusions............................................................................................................................... 23 HABITAT ASSESSMENT OF POTENTIAL RESTORATION SITES..................................... 23 Site identification...................................................................................................................... 24 Habitat Analysis........................................................................................................................ 30 Conservation efforts toward nuthatch habitats ......................................................................... 35 Preliminary population models................................................................................................. 36 LOCATION AND STATUS OF DONOR POPULATIONS....................................................... 40 CONCLUSIONS AND RECOMMENDATIONS ....................................................................... 41 REFERENCES ............................................................................................................................. 44 3 LIST OF TABLES Table 1. Morphological and plumage characteristics of S. c. aculeata and S. c. tenuissima (from Aldrich 1944)................................................................................................................................ 50 Table 2. Recent breeding sites of SBWBNU in the South Puget Sound (from C Chappel, pers. comm.). ......................................................................................................................................... 50 Table 3. Slender-billed White-breasted Nuthatch population trend (percentage change per year) results based on BBS trend data for the period 1966-2004 (From Sauer et al. 2003). ................. 51 Table 4. Vegetation characteristics of SBWBNU nest sites and survey points where SBWBNU were detected and where they were not detected (Viste-Sparkman 2005). .................................. 53 Table 5. Vegetation characteristics of SBWBNU nest sites in oak trees and random oak trees (Viste-Sparkman 2005)................................................................................................................. 53 Table 6. Reproductive measures for White-breasted Nuthatches in North America and Eurasian Nuthatch........................................................................................................................................ 54 Table 7. Number of hectares of management or restoration directed towards oak habitat in the South Puget Sound region............................................................................................................. 55 Table 8. Total number of hectares of oak and pine habitat (ha) at two potential reintroduction sites for SBWBNU in South Puget Sound and the amount of habitat that is potentially suitable for SBWBNUs. ............................................................................................................................. 57 Table 9. List of model inputs for eight population models run with Program Vortex................ 58 Table 10. Model parameters and outcomes of SBWBNU population models (all runs based on 1000 simulations ........................................................................................................................... 61 LIST OF FIGURES Figure 1. Slender-billed White-breasted Nuthatch population trends from Christmas Bird Count Data for Oregon and California sites. Data are 5-year moving averages (i.e, the number of birds per party-hour for each year is the mean of that year’s results plus the two previous years and the two following years....................................................................................................................... 52 Figure 2. Oak habitats at the Fort Lewis and Scatter Creek sites in South Puget Sound (Data from Chappel et al. 2003). ............................................................................................................ 56 Figure 3. Model results showing the mean number of individuals for 1000 simulations (includes successful and extirpated populations) over 100 years................................................................. 59 Figure 4. Model results showing the mean number of individuals for 1000 simulations (includes successful and extirpated populations) over 100 years................................................................. 60 4 INTRODUCTION Conservation efforts aimed at restoring biodiversity increasingly are turning to reintroduction as a tool to reestablish extirpated species to their former range (Griffith et al. 1989). Reintroductions may be required in cases where habitat loss and degradation has created fragmented habitats that prohibit dispersal pathways needed for recolonization. In some situations, reintroductions may be favored to accelerate the recolonization process, even when the extirpated species of interest has strong dispersal capabilities or habitat bridges exist between occupied and unoccupied habitat. Reintroductions are usually performed either through the release of captive-bred individuals or through the translocation of wild individuals from one part of their range to another (Griffith et al. 1989). In response to the increasing frequency with which reintroductions are being attempted, the IUCN (1995) developed guidelines for reintroduction efforts to insure that reintroductions are justifiable, that they are likely to succeed, and that the conservation world can gain knowledge