cerulean warbler: population status and breeding season ......cerulean warbler: population status...
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Cerulean Warbler:Cerulean Warbler:Population Status and Population Status and
Breeding Season Breeding Season MonitoringMonitoring
Kenneth V. RosenbergCornell Lab of Ornithology
Cerulean Warbler Technical Group
November 16, 2006
Cerulean Warbler: distributionCerulean Warbler: distribution
• Breeds in eastern North America
• Winters on east slopes of the Andes in northern South America
• Migrates through Central America and Gulf Coast
Detailed Breeding DistributionDetailed Breeding Distribution• Cerulean Warbler Atlas Project (1996-2003)• Over 3,000 sites surveyed with Ceruleans• Largely restricted to Central Hardwoods biome
Population ConcentrationsPopulation Concentrations67010
1912723
917
1067
9
50
60
5
No. pairs State/Prov Site 430 TN Royal Blue Wildlife Management Area 325 NY Montezuma Wetlands Complex 300 IL Kaskaskia River 240 TN Center Hill Lake, Edgar Evins State Park 200 IN Big Oaks NWR 200 IL Shawnee National Forest 200 ON Queens Univ. Biological Station 175 MI Kalamazoo River, Allegan St. Game Area 165 NY Alleghany St. Pk. And vicinity 145 TN Frozen Head State Park
General Habitat Relationships
• Large tracts of mature deciduous forest
• Ridge tops, floodplain and mesic cove forests.
• Common denominator = emergent, structurally diverse canopy
Variation in Area Sensitivity?
< 50 ac
500-1,000
1-2,000
2-5,000
> 5,00
0 ac
100-200
200-500
50-100< 50 ac
500-1,000
1-2,000
2-5,000
> 5,000 ac
100-200
200-500
50-100
Southeast Northeast
Breeding Season Monitoring
• Expand breeding season distribution surveys– Fill in gaps in core of range (private lands)– Refine global and regional population estimates
• Expand and refine monitoring capabilities– Evaluate credibility of BBS– Monitor trends at population “hot spots”
• Combine monitoring with predictive models– Use modeling to direct inventory and monitoring– Use survey results to refine model development
Priorities
• Expand CEWAP in core of range– Partner with private industrial forest landowners– Use initial models to target habitats– Seek multi-state funding (NFWF)– Use results to expand and refine regional models
• Enhance credibility of BBS– USGS refine analyses and address roadside bias– Assure complete BBS coverage (esp. in core of range)
Breeding Season Monitoring
Action Plan
• Develop new monitoring methodologies to supplement BBS– Identify and re-conduct historical surveys– Develop site-based monitoring, esp. at hot spots
• Develop range-wide modeling strategy– Combine basic models of Knudson, Thogmartin,
Buehler, Sauer, Dettmers– Refine regional models for BCR planning
Action Plan
Breeding Season Monitoring
Surveys on Private Lands (2003Surveys on Private Lands (2003--2006)2006)
• Landowners conducted surveys at 2,200 sites
• Ceruleans were located at roughly 30% of all sites surveyed
• Stratified random sampling in 2006 (Buehler model)
• Will incorporate results into regional models
Proactive partnership with industry – NFWF grant to NCASI
Cerulean Warbler (Survey-Wide
00.20.40.60.8
11.21.4
1966
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
2002
2005
Year
CIHierarchicalCI
Population Trend (BBS Population Trend (BBS ––2006)2006)
-2.9% per year, roughly 70% loss since 1966
Consistency in Regional TrendsCerulean Warbler (Central Hardwoods S24
0
0.2
0.4
0.6
0.8
1
1.2
1 4 7 10 13 16 19 22 25 28 31 34 37 40Year
CIHierarchicalCI
Cerulean Warbler (Appalachians S28
00.5
11.5
22.5
33.5
44.5
1966
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
2002
2005
Year
CIHierarchicalCI
Cerulean Warbler (Great Lakes/St Lawrence S1
0
0.2
0.4
0.6
0.8
1
1.2
1966
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
2002
2005
Year
CIHierarchicalCI
Cerulean Warbler (Prairie Hardwood Trans S2
0
0.1
0.2
0.3
0.4
0.5
0.6
1966
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
2002
2005
Year
CIHierarchicalCI
-3.0% / yr 70% loss
-1.8% / yr 51% loss
-4.4% / yr 83% loss
-2.7% / yr 66% loss
Population Trend Exercise
What was the true historical population trend for Cerulean Warblers rangewide 1966-2005?
Panelists had 100 points to distribute among predetermined categories to reflect their certainty or uncertainty.
LESS DECLINE than BBS credible interval(<2.0%/yr or a positive trend) WITHIN BBS credible interval(between –2.0% & –4.2%/yr)
MORE DECLINE than BBS credible interval(>4.2%/yr decline)
Population Trend Exercise Results
Strong confidence that true trend is within credible interval of BBS trend
Less decline than BBS c.i.(<2.0%/yr decline or positive) 20 10 10 20 20 3 5 5 10 15
Within BBS c.i.(between –2.0 and –4.2%/yr) 70 80 80 60 75 95 80 75 80 75
More decline than BBS c.i.(>4.2%/yr decline ) 10 10 10 20 5 2 15 20 10 10
• Expansion into NY, NJ, New England, e. Ontario during mid-20th century
• Poor BBS coverage
• Recent local declines?
• Repeated Breeding Bird Atlases
Are Ceruleans still expanding into Northeast?
BBS Trends for NY, NJ, New England, and Ontario
Cerulean Warbler, NY, NJ, NE, ONT
0
0.05
0.1
0.15
0.2
1966
1969
1972
1975
1978
1981
1984
1987
1990
1993
1996
1999
2002
2005
Year
CIMedianCI
Trend = +2.2% per year since 1966 – NS
Change in Distribution: OntarioChange in Distribution: Ontario
1985 2005
13% decline in number of blocks with breeding evidence
Change in Distribution: NY +PAChange in Distribution: NY +PA
1985 2005
1989 2006
NY: -13%
PA: -55%(not complete)
Population Status
• BBS – Declines in core of range
• 70% population loss since 1966
• Historic expansion to Northeast – but recent declines?
• Geographic variation in habitat use and area-sensitivity
• Run BBS routes regularly; address biases
• Build monitoring capacity on private lands, off-road, and edge of range – occupancy monitoring?
• Develop and refine range-wide predictive models
• Evaluate parameters for PIF pop estimates
• Establish population goal through CWTG
Breeding Season MonitoringGoal: Improve monitoring for trends, habitat modeling, and population estimation