Bicknell's Thrush: Conservation in fhe Face of Long Odds

Bicknell’s Thrush: Conservation in the Face of Long Odds

Chris Rimmer, Julie Hart, Randy Dettmers, Becky Whittam, Kent McFarland,

and Yves Aubry

Why Bicknell’s Thrush?

Rare

global population < 50,000 individuals

Ranges restricted and fragmented

occupies habitat “islands”

~90% winter population on Hispaniola

At risk

population declines

multiple habitat threats in N. America

severe, ongoing winter habitat loss

Reclusive and Enigmatic

many obstacles to understanding status

few baseline population data

= Vulnerable

Partners In Flight = North America Watch List IUCN Red List = Vulnerable ABC/Audubon WatchList = Red List Canada = Candidate for Federal Listing USFWS = Special Concern ME, NH, NY, VT = Special Concern www.bicknellsthrush.org

George J. Wallace c. 1935 Eugene P. Bicknell c. 1881

The New Generation of BITHnologists Henri R. Ouellet, 1995

BITH Migratory Range “ Islands” north and south Migration routes/patterns = ??

Bicknell’s Thrush Distribution in the U.S. 5 km² 263 km² 88 km² 496 km² 261 km²

Threats to Breeding Habitats

“ Only a freak ornithologist would think of leaving the trails for more than a few feet.” George J. Wallace, 1936

BITH habitat declines sharply with rising temperature 0 20 40 60 80 100 120 140 160 +0 +1 +2 +3 +4 +5 +6 +7 Mean July Temp. Change (°C ) Relative to 1950-1980 BITH Habitat (1,000 ha) Low emissions 2.8°C High emissions 5.9°C

Complex Breeding System Polygynandry: Both males and females mate with multiple partners; paternity is highly mixed Nesting Female Male Home Range r r r r r

n=4 n=4 n=10 n=3 n=5 n=7 Overall mean = 2.2 males : female Breeding Adult Sex Ratios

Hispaniola: winter stronghold of BITH Dominican Republic Haiti DR: ~10% original forest remains Haiti: 1-2% original forest left

Limiting Factors in Winter Habitats

% Unprotected Wet Broadleaf Forest 65.9 Dense Conifer Forest 39.3 Semi-humid Broadleaf Forest 75.9

Strong evidence that females are limited during annual cycle When and where?

Where are Females Limited? Nest 1:1 sex ratio in clutch Fledge Post Fledging Dispersal 1:1 1:1 Fall Migration 1:1 ? 1:1 ? Ratio ? Spring Migration Ratio ? Breeding Grounds >2:1 Cloud Forest >1:1 Rain Forest <1:1 Habitat and Territory Selection

What do we know about BITH populations?

Bicknell’s Thrush in the White Mountains: 7% Annual Decline 9 Years 17 Routes 2002-2008 declines in Canada: New Brunswick – 20%, Nova Scotia – 19%

BITH relative abundance on U.S. routes surveyed annually, 2001-2008

www.bicknellsthrush.org/ International Bicknell’s Thrush Conservation Group (IBTCG) www.bicknellsthrush.org Developing a Conservation Action Plan

IBTCG structure: inclusive, flexible Breeding and Migration Research Breeding and Migration Forestry Wintering Grounds Coordination Committee Breeding and Migration Monitoring

Over-winter Survival Fecundity Autumn Migratory Survival & Seasonal Interactions Spring Migratory Survival & Seasonal Interactions Winter Habitat Amount/quality Direct Mortality Physiological Condition Introduced Predators More Catastrophic Weather Atmospheric Phenomenon (Hg, Pb, Acid Rain) Climate Change Increased Drought & Wind Natural Fires Subsistence Farming & Logging Disease, Parasites, etc. Feral Domestic Animals Human-caused Fires Low Genetic Diversity Breeding Habitat Amount/quality Direct Mortality Breeding Season Survival + Physiological Condition Atmospheric Phenomenon (Hg, Pb, Acid Rain) Climate Change Cone-Squirrel Cycle Disruption Forest Conversion Increased Rain & Wind Forestry Practices Incidental Take Forest Succession Male-biased Sex Ratio Human Disturbance Industrial Development Disease, Parasites, etc. Coastal Development Δ in Prey Emergence Forest Pathogens

Over-winter Survival Fecundity Autumn Migratory Survival & Seasonal Interactions Spring Migratory Survival & Seasonal Interactions Amount of Winter Habitat Direct Mortality Physiological Condition Amount of Breeding Habitat Direct Mortality Breeding Season Survival + Physiological Condition Track effects of climate change ID Important Migratory Sites Determine Forestry Effects Assess Effects of Acid Deposition Monitor Responses to Development Track effects of climate change Develop Forest Mgmt Guidelines and Habitat Supply Analysis ID Where Deforestation is Occurring Prioritize Remaining Forest for Protection Habitat Use and Survival Relative to Land Use and Condition Protection & Restoration of Key Habitats

Primary IBTCG Goals

Estimate the global population of BITH

estimate with 95% CI, which itself is ≤ 20% of population estimate

(e.g., 95% CI of 45–55,000 individuals on a total population est. of 50,000)

* Increase global population of BITH by 50% over the next 50 years

Determine BITH population status annually

density and abundance indices with CV < 0.2

site-specific occurrence data to map rangewide breeding distribution

Document BITH population trends over time

implement Mountain Birdwatch Version 2.0 in 2010

80% power to detect > 3% annual change over 50 years at P < 0.1

Relate BITH population trends and demographics to limiting factors

e.g., habitat/landscape characteristics, climate, red squirrel abundance, Hg exposure, Ca availability, forestry practices, winter habitat extent

Wintering Grounds Conservation Actions Protect, restore, and manage current and potential winter habitat Investigate overwinter survival and demography relative to local habitat condition and quality (connectivity, seasonal carry-over effects) Expand resources and reach of BITH Habitat Protection Fund Clarify BITH distribution and habitat use on other Greater Antillean islands Involve and build capacity of in-country partners

Can we get there from here??