Eastern Meadowlark Evaluation

COSSARO Candidate species at risk evaluation for Eastern Meadowlark (Sturnella magna)

Committee on the status of species at risk in Ontario (COSSARO)
Assessed by COSSARO as Threatened

June, 2011

Final

Part 1 - Current status and distribution

Current designations:

GRANK – G5 (20 Aug. 1999; NatureServe 2011)
NRANK Canada – N5B (25 Jul. 2000; NatureServe 2011)
COSEWIC – Designated Threatened in May 2011.
SARA – No SARA status. ESA 2007 – Not listed.
SRANK – S4B (NHIC 2011).

Distribution in Ontario:

In Ontario, the Eastern Meadowlark's current breeding range extends from the southwestern part of the province more or less continuously north to include southern Algoma, Sudbury and Nipissing districts. It also occurs in a northern pocket of agricultural lands associated with the Little Clay Belt in Timiskaming District. In northwestern Ontario, it is uncommon in the Lake of the Woods area, particularly in agricultural areas of western Rainy River District (Cadman et al. 1987; 2007). The species' occurrence is not necessarily continuous within the broad range depicted, being absent from regions that do not provide suitable grassland habitat (COSEWIC 2011).

Distribution and status outside Ontario:

The global breeding range of the Eastern Meadowlark includes central and eastern United States, and extends to southern Florida and the Gulf Coast. It also breeds in Cuba, Mexico, Central America, and northern South America. In Canada, most of the population breeds in southern Ontario. This bird becomes progressively less common through southern Québec, New Brunswick, and southern Nova Scotia. Eastern Meadowlarks are short-distance migrants, with most of the Ontario population wintering in the south-central and southeastern United States (COSEWIC 2011).

Part 2 - Eligibility for Ontario status assessment

2.1 Application of eligibility criteria

Taxonomic distinctness

Yes. There is no taxonomic uncertainty regarding this species.

Designatable Units

In Canada, only one subspecies (S. magna magna) is recognized, and there is no evidence suggesting more than one designatable unit in Ontario (COSEWIC 2011).

Native status

Yes. Eastern Meadowlarks have been known in Ontario since the mid 1800s (Cadman et al. 1987). Although they became common in southern Ontario along with the clearing of forests for agriculture and settlement, they were probably present before this time in native prairie habitats (Bent 1958).

Presence/absence

Present.

2.2 Eligibility results

Assess whether or not the putative taxon or DU satisfies all eligibility criteria and is therefore subject to further evaluation:

1. The putative taxon or DU is valid. Yes
2. The taxon or DU is native to Ontario. Yes
3. The taxon or DU is present in Ontario, extirpated from Ontario or extinct? Present.

Part 3 - Ontario status based on COSSARO evaluation criteria

3.1 Application of primary criteria (rarity and declines)

1. Global rank

Not in any category. The global rank of species is G5 (NatureServe 2011).

2. Global decline

Endangered. Population trends of Eastern Meadowlark populations breeding outside North America (e.g., Central and South America) are unknown. This criterion, therefore, can only be evaluated with respect to North America.

The Eastern Meadowlark belongs to the group of grassland bird species that has been experiencing widespread declines over the past 50 years. In recent decades, declines have been consistently documented by the North American Breeding Bird Survey (BBS), Breeding Bird Atlases, and Christmas Bird Counts (COSEWIC 2011). In North America, the species experienced a massive loss of prairie habitat following European settlement. Subsequently the species probably increased when large amounts of pastures and hayfields were created with the widespread conversion of eastern deciduous forests to agricultural land. Since the mid 20^th century, however, the amount and quality of pastures and hayfields across its range have declined, following agricultural modernization reforestation of marginal farmlands, and the large-scale conversion of forage crops into row crops. Native prairie grasslands have not been restored, and persist only in small fragments in Ontario and elsewhere (COSEWIC 2011). While this species likely had a less extensive breeding range prior to European settlement, it is not possible to determine the degree to which the current population size resembles the prehistoric condition.

Breeding Bird Survey data from across North America indicate a decline of 3.1%/year between 1966 and 2009 (C.I. = -3.5%, -2.9%) and 2.2%/year between 1999 and 2009 (C.I. = -2.7%, -1.7%) (Sauer et al. 2011). This corresponds to a decline of 74% from 1966 to 2009. The short-term (1999-2009) trend was -2.2% (CI= -2.7% to -1.7%), representing a population decline of 20% between 1999 and 2009, which corresponds roughly with three generations.

Christmas Counts conducted within about 58% of the wintering range of eastern meadowlarks in the U.S. estimated a trend of -3.35% per year (95% CI = -3.8% to - 2.8%; n =1492) across an area (Butcher and Niven 2007). This translates to a 74% loss over the entire 39-year period, with no signs of leveling off. Both measures of Eastern Meadowlark decline meet COSSARO's threshold for global decline of Endangered.

3. Northeastern North America ranks

Not in any category. Eastern Meadowlark is ranked as S1 in Nova Scotia and S2 in New Brunswick, but is otherwise ranked as S3 or higher in all other northeastern North American jurisdictions where it is resident (Appendix 1).

4. Northeastern North America decline

Endangered. The Eastern Meadowlark likely occurred across much of its present-day range historically, albeit its distribution in the east was likely scattered (Askins 1999). As noted above, in the late 1800s and early 1900s regional population increases in eastern Canada may have occurred, fueled by the creation of large amounts of surrogate grasslands habitat (i.e., pastures, hayfields) that accompanied deforestation (COSEWIC 2011).

The Ontario Breeding Bird Atlas, the Maritimes Breeding Bird Atlas and the Étude des populations d'oiseaux du Québec, have indicated significant declines in recent decades. In the Maritimes, a comparison of the raw counts of occupied squares during the first breeding bird atlas (1986-1990) with the second atlas 20 years later (2006-2010) suggested a decline in occupancy of about 55% – from 29 10x10 km squares in the first atlas to 13 in the second (BSC 2011). It is unknown how this correlates with the functional loss of pastures and hayfields as Eastern Meadowlark habitat. A somewhat more refined estimate that attempted to take observer effort into account yielded a change of about -45% between the two atlas periods (B. Whittam pers. comm. 2011 in COSEWIC 2011). The 10-year change was about -23%. The ÉPOQ/SQBP database showed a significant long-term decline in Eastern Meadowlark records in Québec of 2.4% per year (R2= 0.81; P ≤ 0.001) between 1970 and 2008, representing a 60% decline over 38 years. There is an indication that the negative trend in Québec may be showing signs of stabilizing in recent years.

Breeding Bird Survey data have shown declining Eastern Meadowlark populations in all nine Bird Conservation Regions covering Northeastern North America jurisdictions where this species occurs. Declines range from 2.2%/year to 6.4 %/year between 1966 and 2009 (Sauer et al. 2011). This corresponds to 62% to 94% from 1966 to 2009 or 15% to 58% over the last 10 years. Only three of the nine Bird Conservation Regions show long-term declines of less than 70%, while five are under the 30% threshold for declines having taken place over three generations (Table 1). Of 25 jurisdictions in Northeastern North America where Eastern Meadowlarks are known to occur, 23 (92%) have had long-term (1966-2009) trends exceed -50%, and 17 (68%) have had 10-year declines of more than 30% (Sauer et al. 2011; Appendix 1).

Table 1. Eastern Meadowlark population trends (including upper and lower confidence intervals) in 9 Bird Conservation Regions covering Northeastern North America (Sauer et al. 2011).

5. Ontario occurrences

Not in any category. The number of Ontario occurrences is unavailable from the Natural Heritage Information Centre, which describes it as a "common breeding species throughout its Ontario range (NHIC 2011). Based on Breeding Bird Atlas data from 2001-05, the Ontario population was estimated at 150,000 birds (Blancher and Couturier 2007).

6. Ontario decline

Threatened. A comparison of the species probability of detection in Ontario from the first (1981-1985) to the second (2001-2005) atlas period showed an overall significant decline of 13% in occupancy across the province as a whole, with significant regional declines ranging from 9-17% in the Southern Shield, Lake Simcoe-Rideau and Carolinian regions (Cadman et al. 2007). A non-significant decline was found for the Northern Shield region (Cadman et al. 2007). It should be noted that atlas distributional changes in occupancy underestimate change in actual abundance for widespread common birds like Eastern Meadowlarks (Francis et al. 2009).

Using a hierarchical spatial model, the most recently analysed trend estimates for Eastern Meadowlarks in Ontario demonstrated an average annual long-term decline (1966-2009) of 2.4% (CI -3.0 to -1.7%) with a short-term (1999-2009) trend of -2.8% (CI= -4.1% to -1.4%). This corresponds with an overall long-term trend of -64.8% and a 10-yr trend of -24.7% (Sauer et al. 2011). The confidence intervals of both trend estimates place long-term and short-term decline estimates over the COSSARO thresholds for Endangered and Threatened, respectively.

There have also been declines in area of occupancy, and in quantity and quality of habitat, which began in the mid-20^th century. Causes of population decline of Eastern Meadowlarks, while largely understood and potentially reversible, have decreased somewhat in annual rate, but have not ceased and show little evidence of stabilization or improvement (COSEWIC 2011).

7. Ontario's conservation responsibility

Not in any category. The bulk of the Canadian population breeds in Ontario (roughly 70%), but this is <10% of global range.

3.2 Application of secondary criteria (threats and vulnerability)

8. Population sustainability

Insufficient information. No information from Ontario.

9. Lack of regulatory protection for exploited wild populations

Not in any category. In Canada, the Eastern Meadowlark and its nests and eggs are protected under the Migratory Birds Convention Act.

10. Direct threats

Threatened. The main causes of the decline in Eastern Meadowlark populations have been identified as: 1) habitat loss on the breeding grounds (and probably also on the wintering grounds) caused by large-scale conversion of forage crops to intensive grain crops and other row crops, reforestation of abandoned farmlands, and urbanization; 2) intensification and modernization of agricultural techniques promoting earlier and more frequent haying during the nesting season, which results in low breeding success; 3) a high (and probably increasing) rate of nest predation; 4) overgrazing by livestock; 5) mortality due to pesticide use on the breeding and wintering grounds; and 6) reduced reproductive output stemming from Brown-headed Cowbird (Molothrus ater) nest parasitism (COSEWIC 2011).

Recent trends in agricultural land use in Ontario for the period 1981 to 2006 from Statistics Canada's Census of Agriculture (2006) show that total farm acreage declined by about 11%; the amount of land used for improved and unimproved pasture decreased by about 54% and 28%, respectively; the amount of land in summer fallow decreased by 81%; and the amount of farmland used for crops increased by about 1%. In parts of Ontario, the natural succession of abandoned agricultural fields is thought to be largely responsible for the species' decline (Cadman et al. 2007). Within the remaining breeding habitat, there have also been range-wide trends toward earlier and more frequent mowing of hay crops, which reduces habitat quality directly because it results in large reductions in nest productivity (e.g., Lanyon 1995; Granfors et al.1996; With et al. 2008).

Tallgrass prairie and savannah habitats in southern Ontario are reduced to just a few thousand hectares, or only 3% of their historic extent (Tallgrass Ontario 2011). While potential habitat in the form of hayfields or pastures have increased at least 10-fold since that time (OMAFRA 2011), there is no available information on how much of this has been lost as habitat for this grassland specialist since the 1960s and how much remains today. Native grasslands continue to be adversely affected by encroachment of woody vegetation in the absence of wildfires, grazing or active management; tree planting; and expansion of rock quarries in alvar habitats. Despite the large-scale conversion of the eastern forest to forage crops and dairy farms in the 1800s and early 1900s – a time at which Eastern Meadowlarks clearly benefited (Cadman et al. 1987; Gauthier and Aubry 1995) – market pressures and modern agricultural practices that involve increased mechanization rapidly converted forage crops (i.e., pastures and hayfields) to intensive cereal and row crops. This has likely been partly responsible for the recent negative trends in Eastern Meadowlark populations (Jobin et al. 1996; Corace et al. 2009).

Since at least the 1950s, increased mechanization and the use of more intensive management practices in agriculture have favoured earlier and more frequent hay cutting (up to three harvests between June 15 – August 15 for Canada), which is known to reduce nest productivity as a consequence of the high rate of mortality in young and adult Eastern Meadowlarks during the breeding season (e.g., Lanyon 1995; Granfors et al.1996; Nocera et al. 2005, 2007; With et al. 2008).

Several studies have suggested that predation is a major source of nest failure of several grassland bird species, including Eastern Meadowlark (e.g., Granfors et al. 1996; Renfrew et al. 2005; Perkins and Vickery 2007).

11. Specialized life history or habitat-use characteristics

Not in any category The Eastern Meadowlark is most common in native grasslands, pastures and savannas (Lanyon 1995; COSEWIC 2011). It also uses a wide variety of other anthropogenic grassland habitats. As with other grassland bird species, the suitability of grassland habitat for Eastern Meadowlark involves a combination of landscape and patch characteristics (Vickery et al.1994; Renfrew and Ribic 2008). As a short-distance migrant, it may be less vulnerable to threats associated with long migration.

3.3 COSSARO evaluation results

1. Criteria satisfied in each status category

Number of primary and secondary criteria met in each status category:

Endangered – [2/0]
Threatened – [1/1]
Special concern – [0/0]

Number of Ontario-specific criteria met in each status category:

Endangered – [0]
Threatened – [1]
Special concern – [0]

2. Data deficiency

No. The number of criteria assessed as "insufficient information" is 1 (population sustainability).

3. Status based on COSSARO evaluation criteria

The application of COSSARO evaluation criteria suggests that Eastern Meadowlark is Threatened in Ontario.

Part 4 - Ontario status based on COSEWIC evaluation criteria

4.1 Application of COSEWIC criteria

Regional (Ontario) cosewic criteria assessment

Criterion A – decline in total number of mature individuals

Threatened, A2bc. Marginally meets Threatened A2bc. The most recently analysed trend estimates for Eastern Meadowlarks in Ontario demonstrated an average annual short-term (1999-2009) trend of -2.8% (CI= -4.1% to -1.4%), corresponding with a 3- generational trend that ranges from -34.2 to -13.2% (Sauer et al. 2011).

Criterion B – Small distribution range and decline or fluctuation

Not in any category Does not meet criterion; exceeds thresholds for extent of occurrence and area of occupancy.

Criterion C – Small and declining number of mature individuals

Not in any category Does not meet criterion; exceeds thresholds for population size.

Criterion D – Very small or restricted total population

Not in any category Does not meet criterion; exceeds thresholds for population size, area of occupancy and number of locations.

Criterion E – Quantitative analysis

Insufficient information.

Rescue Effect

No. In the event of the extirpation of the Canadian population, immigration of individuals from U.S. jurisdictions is possible. However, nearly every state, including all northern states bordering Canada, shows a statistically significant population decline. Across the Eastern Meadowlark's range in the U.S., all survey data point to long-term, statistically significant annual declines, making rescue unlikely (see Global and Northeastern North America declines section above).

Special Concern Status

N/A.

4.2 COSEWIC Evaluation results

1. Criteria satisfied in each status category

Endangered – [no]
Threatened – [yes]
Special concern – [no]

2. Data deficiency

No.

3. Status based on COSEWIC evaluation criteria

The application of COSEWIC evaluation criteria suggests that Eastern Meadowlark is Threatened in Ontario.

Part 5 - Ontario status determination

5.1 Application of COSSARO and COSEWIC criteria

COSSARO and COSEWIC criteria give the same result. Yes

5.2 Summary of status evaluation

Eastern Meadowlark is classified as Threatened in Ontario.

This medium-sized songbird is a member of the blackbird family and is one of most recognizable of Ontario's grassland birds. A ground-nesting bird with a bright-yellow throat and belly, this species joins other grassland birds of North America in having experienced widespread declines over the past 50 years. Its breeding range extends from the Atlantic coast, through the Great Plains, south to Florida and Arizona, and through Mexico to northern South America and Cuba. Seventy percent of Canada's population breeds in southern Ontario; it is progressively less common in southern Québec, New Brunswick, and southern Nova Scotia. In Ontario, it is continuously distributed south of the Canadian Shield, and also nests in the Lake Nipissing area, the Clay Belt, and the Rainy River area. Although still relatively common in Ontario, it has been declining here, as it has throughout its North American range, since the 1960s. This is mostly likely due to loss of grassland habitat on both the breeding and wintering grounds, coupled with reduced reproductive success resulting from early haying. Long- term monitoring data from a number of sources indicates population declines exceeding 70% across North America and in Ontario. Eastern Meadowlark is classified as Threatened in Ontario due to declining populations and on-going threats of habitat loss and degradation.

Information Sources

Literature cited

Askins, R.A. 1999. History of grassland birds in eastern North America. In Ecology and Conservation of Grassland Birds in the Western Hemisphere (P. Vickery and J. Herkert, eds.). Studies in Avian Biology 19:60-71.

Bent, A.C. 1958. Life Histories of North American Blackbirds, Orioles, Tanagers, and Allies. U.S. National Museum Bulletin 211. Pp. 28-52.

Bird Studies Canada (BSC). 2011. Maritimes Breeding Bird Atlas. Web site: http://www.mba-aom.ca/english/index.html [accessed May 2011].

Blancher, P. and A.R. Couturier. 2007. Population size estimates for Ontario birds, based on point counts. Pp. 655–657 in M.D. Cadman, D.A. Sutherland, G.G. Beck, D. Lepage, and A.R. Couturier (eds.). 2007. Atlas of the Breeding Birds of Ontario, 2001-2005. Bird Studies Canada, Environment Canada, Ontario Field Ornithologists, Ontario Ministry of Natural Resources, and Ontario Nature, Toronto, xxii + 706 pp.

Butcher, G.S., and D.K. Niven. 2007. Combining data from the Christmas Bird Count and the Breeding Bird Survey to determine the continental status and trends of North America birds. National Audubon Society, New York, NY. http://www.audubon.org/bird/stateofthebirds/CBID/report.php.

Cadman, M.D., P.F.J. Eagles, and F.M. Helleiner (eds.). 1987. Atlas of the Breeding Birds of Ontario. University of Waterloo Press. Waterloo, ON.

Cadman, M.D., D.A. Sutherland, G.G. Beck, D. Lepage, and A.R. Couturier (eds.). 2007. Atlas of the Breeding Birds of Ontario, 2001-2005. Bird Studies Canada, Environment Canada, Ontario Field Ornithologists, Ontario Ministry of Natural Resources, and Ontario Nature, Toronto, xxii + 706 pp.

Census of Agriculture. 2006. 2006 Census of Agriculture, Farm Data, Initial Release. Statistics Canada.www.statcan.ca/english/freepub/95F0301XIE/tables.htm

Corace III R.G., Flaspohler D.J. and L.M. Shartell. 2009. Geographical patterns in openland cover and hayfield mowing in the Upper Great Lakes region: implications for grassland bird conservation. Landscape Ecology 24:309-323.

COSEWIC 2011. COSEWIC Status Report on the Eastern Meadowlark Sturnella magna. Prepared for the Committee on the Status of Endangered Wildlife in Canada. Environment Canada, Ottawa.

Francis C.M., P.J. Blancher and R.D. Phoenix. 2009. Bird monitoring programs in Ontario: what have we got and what do we need? The Forestry Chronicle 85: 202-217.

Gauthier, J. and Y. Aubry (sous la direction de). 1995. Les oiseaux nicheurs du Québec: Atlas des oiseaux nicheurs du Québec méridional. Association québécoise des groupes d'ornithologues, Société québécoise de protection des oiseaux, Service Canadien de la faune, Environnement Canada, Montréal, xviii + 1295 p.

Granfors, D.A., K.E. Church, and L.M. Smith. 1996. Eastern Meadowlarks nesting in rangelands and conservation reserve program fields in Kansas. Journal of Field Ornithology 67:222-235.

Jobin, B., J.-L. Desgranges, and C. Boutin. 1996. Population trends in selected species of farmland birds in relation to recent developments in agriculture in the St. Lawrence Valley. Agriculture, Ecosystems and Environment 57:103-116.

Lanyon, W. E. 1995. Eastern Meadowlark (Sturnella magna). A. Poole and F. Gill, editors. The Birds of North America, No. 160. The Academy of Natural Sciences, Philadelphia, PA.

NatureServe. 2011. NatureServe Explorer: An Online Encyclopedia of Life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer [accessed May 2011].

Nocera J.J., G.J. Parsons, G.R. Milton, and A.H. Fredeen. 2005. Compatibility of delayed cutting regime with bird breeding and hay nutritional quality. Agriculture, Ecosystems and Environment. 107:245-253.

Nocera, J.J., G. Forbes, and G. Milton 2007. Habitat relationships of three grassland breeding bird species: broadscale comparisons and hayfield management implications. Avian Conservation and Ecology - Écologie et conservation des oiseaux 2:7. [online] URL: http://www.ace-eco.org/vol2/iss1/art7/

Ontario Ministry of Agriculture, Food, and Rural Affairs (OMAFRA) 2011. Statistical Summary of Ontario Agriculture. Available at http://www.omafra.gov.on.ca/english/stats/agriculture_summary.htm [accessed May 2011].

Perkins, D.W., and P.D. Vickery. 2007. Nest success of grassland birds in Florida dry prairie. Southeastern Naturalist 6:283–292.

Renfrew, R.B. and C.A. Ribic. 2008. Multi-scale models of grassland passerine abundance in a fragmented system in Wisconsin. Landscape Ecology 23:181-193.

Renfrew, R.B., C.A. Ribic, and J.L. Nack. 2005. Edge avoidance by nesting grassland birds: a futile strategy in a fragmented landscape. Auk 122:618-636.

Sauer, J.R., J.E. Hines, J.E. Fallon, K.L. Pardieck, D.J. Ziolkowski, Jr., and W.A. Link. 2011. The North American Breeding Bird Survey, Results and Analysis 1966-2009. Version 3.23.2011 USGS Patuxent Wildlife Research Center, Laurel, MD. [accessed May 2011].

Tallgrass Ontario. 2011. Tallgrass and savanna in Ontario. http://www.tallgrassontario.org/TS_SAR.htm [accessed May 2011].

Vickery, P.D., M.L. Hunter, Jr., and S.M. Melvin. 1994. Effects of habitat area on the distribution of grassland birds in Maine. Conservation Biology 8:1087-1097.

With, K.A., A.W. King, and W.E. Jensen. 2008. Remaining large grasslands may not be sufficient to prevent grassland bird declines. Biological Conservation 141:3152-3167.

2. Community and Aboriginal traditional knowledge sources

None.

3. Acknowledgements

Thanks to Jon McCracken, co-chair of the COSEWIC Birds Specialist Subcommittee, for providing additional insight and information towards the preparation of this evaluation.

Appendix 1

Northeastern North America status rank and decline

Occurs as a native species in 25 of 29 northeastern jurisdictions

Srank or equivalent information available for 24 of 25 jurisdictions = (96%) S1, S2, SH, or SX in 2 of 24 = (8%)