Dendroica kirtlandii

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	Passeriformes	Parulidae

Scientific Name:

Dendroica kirtlandii

Species Authority:

(Baird, 1852)

Common Name/s:

English

–

Kirtland's Warbler

Assessment Information [top]

Red List Category & Criteria:

Near Threatened ver 3.1

Year Assessed:

2008

Assessor/s

BirdLife International

Evaluator/s:

Bird, J. & Butchart, S. (BirdLife International Red List Authority)

Justification:
Since 1987, conservation action has successfully increased the population of this species. Numbers exceeded 500 singing males in 1994 following doubling of suitably aged habitat between 1987 and 1990. Numbers continue to increase, but its population and range remain small, hence its classification as Near Threatened.

History:

2005	–	Near Threatened
2004	–	Vulnerable
2000	–	Vulnerable
1994	–	Vulnerable
1988	–	Threatened

Geographic Range [top]

Range Description:	Dendroica kirtlandii breeds in north and central Michigan, with small numbers (and occasional breeding) in Michigan's Upper Peninsula and Wisconsin, USA. Breeding was also recorded in Canada in 2007 for the first time since 1945¹⁷. Breeding habitat has declined by 33% since the 1960s, but is more extensive than the 18 km² occupied in 1994⁹. It has a very small winter range in the Bahamas and the Turks and Caicos Islands (to UK), either concentrated in the northern islands or spread throughout the Bahama Archipelago^5,12. There were major declines in c.1900-1920 and 1961-1971⁵, with the population just 167 singing males in 1974 and 1987². Numbers have recovered to 1,478 singing males in Michigan in 2006, the highest since surveys began in 1951^7,16.
Countries:	Native: Bahamas; Turks and Caicos Islands; United States Vagrant: Bermuda Present - origin uncertain: Canada
Range Map:	(click map to view full version)

Population [top]

Population:	Assuming equal sex ratio, the global population is likely to number c. 3,000 individuals based on 1,478 singing males recorded during surveys in 2006. Until better data are available this is precautionarily interpreted here as 2,500 mature individuals.
Population Trend:	Increasing

Habitat and Ecology [top]

Habitat and Ecology:	Optimal breeding habitat is fire-maintained homogeneous stands of 2-4 m tall jack pines Pinus banksiana on sandy soil^8,11. Eggs are laid in May-June³. Wintering habitat is either primarily Caribbean pine P. caribbaea⁵, or natural and secondary scrub, and saline/upland ecotone¹². Birds move from patch to patch in the wintering grounds as food supplies are depleted and areas dry out, eventually concentrating in small patches where they maintain small and overlapping home ranges¹⁵.
Systems:	Terrestrial

Habitat and Ecology:

Optimal breeding habitat is fire-maintained homogeneous stands of 2-4 m tall jack pines Pinus banksiana on sandy soil^8,11. Eggs are laid in May-June³. Wintering habitat is either primarily Caribbean pine P. caribbaea⁵, or natural and secondary scrub, and saline/upland ecotone¹². Birds move from patch to patch in the wintering grounds as food supplies are depleted and areas dry out, eventually concentrating in small patches where they maintain small and overlapping home ranges¹⁵.

Systems:

Terrestrial

Threats [top]

Major Threat(s):	If scrub is the preferred winter habitat, key threats are fire suppression and brood-parasitism by Brown-headed Cowbirds Molothrus ater in Michigan¹². If Caribbean pine is preferred, habitat loss on the wintering ground is probably more important⁵. The latter is considered likely because of the failure to occupy all breeding habitat, and changes in population have occurred contemporaneously with the degradation and recovery of the north Bahamas pine ecosystem⁵. Recently however the four-fold population increase between 1990 and 2000, coincident with a tripling of the available habitat through management, would appear to indicate that currently population levels are closely linked to habitat availability¹⁴. Consequentially, the current breeding range is too large for fire to affect the whole population rapidly.

Major Threat(s):

If scrub is the preferred winter habitat, key threats are fire suppression and brood-parasitism by Brown-headed Cowbirds Molothrus ater in Michigan¹². If Caribbean pine is preferred, habitat loss on the wintering ground is probably more important⁵. The latter is considered likely because of the failure to occupy all breeding habitat, and changes in population have occurred contemporaneously with the degradation and recovery of the north Bahamas pine ecosystem⁵. Recently however the four-fold population increase between 1990 and 2000, coincident with a tripling of the available habitat through management, would appear to indicate that currently population levels are closely linked to habitat availability¹⁴. Consequentially, the current breeding range is too large for fire to affect the whole population rapidly.

Conservation Actions [top]

Conservation Actions:	Conservation actions underway: CMS Appendix I. Management replicating the effects of natural fires has expanded potential breeding habitat to c.516 km² ^10,11. Since 1972, a cowbird trapping programme has reduced parasitism from 70% to 3%². Education and ecotourism initiatives in Michigan include an annual Kirtland's Warbler Festival¹⁰. Surveys have been undertaken in the Bahamas, most recently in 1998^4,5. There is a project in progress to establish the principal wintering habitat⁶. Virtually the entire population breeds within the 140,000-acre Kirtland's Warbler Management Area which includes the Huron National Forest, the Kirtland's Warbler National Wildlife Refuge and various Michigan state forests. Conservation actions proposed: Ascertain winter habitat requirements. Continue existing initiatives - this will need $1 million per year to maintain it¹³. Study the effects of management on breeding ecology¹¹. Implement prescribed burning for all breeding habitat¹¹. This is not possible in many areas, where it has been replaced by commercial clearouts, followed by a replant or re-seed¹³. Increase the area of jack pine - this is difficult to maintain due to the cost, and its future is uncertain because of the loss of the carbon sequestration program¹³. Investigate more economical cowbird control¹¹.

Conservation Actions:

Conservation actions underway:

CMS Appendix I. Management replicating the effects of natural fires has expanded potential breeding habitat to c.516 km² ^10,11. Since 1972, a cowbird trapping programme has reduced parasitism from 70% to 3%². Education and ecotourism initiatives in Michigan include an annual Kirtland's Warbler Festival¹⁰. Surveys have been undertaken in the Bahamas, most recently in 1998^4,5. There is a project in progress to establish the principal wintering habitat⁶. Virtually the entire population breeds within the 140,000-acre Kirtland's Warbler Management Area which includes the Huron National Forest, the Kirtland's Warbler National Wildlife Refuge and various Michigan state forests.

Conservation actions proposed:

Ascertain winter habitat requirements. Continue existing initiatives - this will need $1 million per year to maintain it¹³. Study the effects of management on breeding ecology¹¹. Implement prescribed burning for all breeding habitat¹¹. This is not possible in many areas, where it has been replaced by commercial clearouts, followed by a replant or re-seed¹³. Increase the area of jack pine - this is difficult to maintain due to the cost, and its future is uncertain because of the loss of the carbon sequestration program¹³. Investigate more economical cowbird control¹¹.

Citation:	BirdLife International 2008. Dendroica kirtlandii. In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. <www.iucnredlist.org>. Downloaded on 21 November 2009.
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