Wildlife Populations

> Changing Arctic environment may increase polar bear predation of birds' nests

Scientists observed polar bears consuming large amounts of bird eggs and chicks in Hudson Bay, an occurrence that may become increasingly common and likely results from early regional break-up of sea ice.

Historically, Hudson Bay polar bears have come ashore at the end of July, after most birds have hatched. However, scientists are seeing bears arriving on land up to a month earlier than 20 years ago, roughly corresponding with the advancing date of sea ice break-up. Polar bears typically focus heavily on marine mammals as prey. Scientists attribute the use of eggs as a food source to mismatched phenology in the changing Arctic environment. Nest initiation for arctic birds, including snow geese and thick-billed murres, has not kept up with the pace of change. As a result, the bears’ arrival on land overlaps with nesting.

Polar bear raids on bird colonies in other areas of the Arctic may also have increased. In 2000 and 2003, two bears scaled cliffs to feed on eggs and young of thick-billed murres nesting on Coats Island. This behaviour was not seen before on Coats Island. In 2004, a lone bear decimated a snow goose colony on Southampton Island and caused complete local breeding failure. Observations of several bears consuming snow goose nests were also made at Coats Island in 2006.

Polar bears have been observed eating terrestrial fare in the past including grasses, algae and berries. They will also eat fish, rodents, caribou and birds. They are opportunistic hunters on land and are believed to derive little nutritional benefit, relying instead on stored fat during ice-free seasons. Eggs appear to offer a potentially significant food source.

These unusual observations, although anecdotal, highlight the complex ecological interactions that are occurring in the changing Arctic environment. Other factors might also increase overlap between bears and birds, such as the expanding population of snow geese forming new colonies in areas frequented by polar bears.

The observations were published in the scientific journal, Polar Biology:

Smith, P.A., K.H. Elliott, A.J. Gaston and H.G. Gilchrist. 2010. Has early ice clearance increased predation on breeding birds by polar bears? Polar Biology 33: 8 (1149-1153).

Contact: Paul Smith (613) 998-7362

> Six priority actions required to conserve vulnerable landbird populations

Hundreds of scientists across Canada, the United States and Mexico have completed a conservation assessment of all species of landbirds in North America. Landbirds have experienced steep declines in abundance and diversity in the past 50 years.

Of the 882 bird species, 148 (17%) require immediate conservation action including hawk-eagles, prairie chickens, guans, wood partridges, quetzals, sage-grouse, Cyanolyca jays and macaws. The habitats most needing protection to support bird populations are tropical forests and pine-oak forests in Mexico, temperate forests, wetlands and grasslands.

The report, Saving Our Shared Birds, recommends six priority actions to protect, restore and enhance bird populations and habitats. The scientific team behind the report assigned regional and continental conservation priorities through the assessment process. Each species was ranked according to vulnerability, based on factors such as population size, distribution, trends and threats. Species ranges were overlapped on digital maps to identify the geographic areas where conservation action is most urgently required.

Six conservation priorities for action:

• protect and recover species of greatest risk, through networks of protected areas, especially in tropical and pine-oak forests in Mexico
• conserve habitats and ecosystem functions through policy changes that support sustainable agriculture, forestry, and urban planning, and incentive programs to increase the uptake of changes in communities and businesses
• reduce sources of bird mortality like window collisions, pesticide poisonings, domestic cat predation, and unsustainable trapping for the pet industry
• expand scientific knowledge of distribution patterns, migratory connectivity, factors that limit bird survival and productivity, and the response of populations to management practices
• engage communities in conservation actions
• increase international partnerships like Joint Ventures and community-based partnerships, and develop new mechanisms to engage business, industry and NGO sectors to find economically viable conservation solutions

Loss of habitat from agriculture, forestry, urbanization and climate change emerged as the major threat to the most vulnerable birds. Conservation plans are needed that take into account the socio-economic needs of human communities in high-pressure areas.

Partners in Flight is a partnership to conserve birds, bringing together governments, industry, non-government organizations and many other groups.

Read about the assessment process behind the report:

• Partners in Flight Species Assessment Database

Citation for the report:

Berlanga, H., J. A. Kennedy, T. D. Rich, M. C. Arizmendi, C. J. Beardmore, P.J. Blancher, G. S. Butcher, A. R. Couturier, A. A. Dayer, D. W. Demarest, W. E. Easton, M. Gustafson, E. Inigo-Elias, E. A. Krebs, A. O. Panjabi, V. Rodriguez Contreras, K. V. Rosenberg, J. M. Ruth, E. Santana Castellon, R. Ma. Vidal, and T. Will. 2010. Saving Our Shared Birds: Partners in Flight Tri-National Vision for Landbird Conservation. Cornell Lab of Ornithology: Ithaca, NY

Contact: Judith Kennedy (819) 934-6065 or Peter Blancher (613) 998-7311

> Captive-release eastern loggerhead shrikes breeding in wild

A pair of endangered eastern loggerhead shrikes has fledged three young birds in Quebec. This is the only known successful shrike breeding in Quebec in the past 15 years. The eastern loggerhead shrike has been designated as endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and is extirpated from much of its historical range.

The female bird was released in Carden, Ontario in 2009 from a captive breeding and release program. She paired with an unbanded one-year-old male. This event confirms the connection between the shrike populations of western Quebec and Ontario. It also suggests that released juveniles will disperse widely from their natal site. In 2009, a male released in Breckenridge, Quebec the previous year was found breeding 253 km south-west of the fledging site. Wide dispersal complicates population surveys but indicates that establishment of one release site can help re-establish the population at several sites.

Returns of captive-release birds to breed in Canada confirm the importance of the release program in supporting species recovery. Another bird from the program bred in Ontario this year, joining less than 100 individuals estimated to breed in that province. Due to harsh conditions in the birds’ wintering areas over the past year, breeding numbers were expected to be down from the 31 pairs documented in 2009. Only 22 pairs were recorded in 2010.

The captive-release program, begun in 1997, is overseen by the Eastern Loggerhead Shrike Recovery Team which includes Environment Canada (Canadian Wildlife Service), Bird Studies Canada, the Federation of Ontario Naturalists, McGill University, the Ontario Ministry of Natural Resources, the Metro Toronto Zoo and Wildlife Preservation Canada. This program is one of the first in the world to deal with a migratory passerine and what is learned should help in the recovery of other species.

Contact: Jean-Pierre Savard (418) 648-3500

Habitats and Ecosystems

> Trends in agricultural impact and recovery for Canada’s prairie wetlands

A large-scale study has documented the degradation of wetlands across the Canadian prairies. More than 90% of the surveyed wetlands had visible agricultural impacts, according to the analysis of more than 10,000 wetlands over a two-decade span. Based on the high rate of impact and slow rate of recovery in prairie wetlands, the researchers recommend stronger wetland protection measures.

The study incorporated wetland habitat data collected on waterfowl survey routes using a novel method to explore how agriculture has affected wetland impact and recovery rates in Manitoba, Saskatchewan and Alberta. The analysis covered impacts on both the wetland margins – the area immediately surrounding flooded basins - and basins, and considered variables like location, year, seasonal wetness, wetland water permanence and surrounding land-use.

The research shows that wetlands at highest risk of long-lasting impact are shallow, temporary and seasonal, and found on cultivated or pasture lands. Researchers believe these wetlands and any remaining pristine wetlands should be of highest conservation priority. By comparison, wetlands with higher water permanence located in natural grass and wooded areas are less affected by agriculture and recover more quickly. Researchers say this highlights the importance of considering adjacent land-use in conservation planning for habitats and for species such as birds or amphibians.

The percentage of wetlands with affected margins stabilized in the early 1990s and remained at those levels upon study completion. In general, wetland margins in all three provinces and across wetland types had higher impact rates than recovery rates, and were more likely than basins to be affected by agriculture. Wetland basins tended to fluctuate with seasonal wetness conditions in their responses to impact and recovery rates. In wetter years, impact rates were lower and recovery rates were higher indicating that these systems are resilient and may recover quickly if given protection.

Although land conversion to agriculture has slowed, activities on existing farmland have intensified, potentially increasing the pressure on wetland margins and offering less opportunity for recovery. If the prairie climate becomes progressively drier, as some climate models predict, agricultural practices will have a greater impact on these ecosystems.

This is among the first studies to apply multistate models to quantify wetland impact and recovery rates, and to consider variation in these rates due to flooding, location and land-use. The researchers suggest their methodology could be used to measure recovery and impact rates in these and other systems, for instance, in response to changes in policies or other interventions.

The study was published in the scientific journal, Ecological Applications:

Bartzen, B.A., K.W. Dufour, R.G. Clark, and F.D. Caswell. 2010. Trends in agricultural impact and recovery of wetlands in prairie Canada. Ecological Applications 20(2): 525-538.

Contact: Bob Clark (306) 975-4110

Health Effects of Toxics

> Amphibians in pesticide-treated agricultural landscape show reduced hatching ability

Twelve current-use pesticides and seven water chemistry parameters have been associated with a significant reduction in amphibian hatching success, according to a two-year study in British Columbia’s Okanagan Valley. The valley is representative of conditions in other heavily farmed areas in North America such as southern Ontario and California’s central valley.

The study looked at egg-hatching success on pesticide-treated agricultural land, organic orchards and conservation areas used as control sites. Researchers detected pesticides in sites up to 500 metres from sprayed sites, indicating that most ponds in the Okanagan Valley are exposed to pesticides.

Hatching success varied among species and sites. The great basin spadefoot, a species at risk of extinction, completely failed to hatch on some pesticide-treated agricultural lands, compared with an 80% general success rate in non-agricultural conservation areas. The western toad, a species of special concern, and the Columbia spotted frog showed similar inability to hatch on pesticide-treated land. Hatching success for the Pacific tree frog, the most common of the four species studied, correlated to water chemistry characteristics and not to pesticides.

Concentrations of individual chemicals found in ponds were not enough to cause acutely toxic responses in amphibian larvae. However, the collective concentration and combination of chemicals may act together to reduce survival and growth of larvae. Interactions among chemicals, combined with water chemistry parameters, may influence amphibian development at levels not currently considered toxic to aquatic life. Water quality guidelines for aquatic life are currently based largely on toxicity to fish and invertebrates, not amphibians.

The study was published in the scientific journal, Environmental Toxicology and Chemistry:

Bishop, C.A., S.L. Ashpole, A.M. Edwards, G. van Aggelen and J.E. Elliott. 2010. Hatching success and pesticide exposures in amphibians living in agricultural habitats of the South Okanagan Valley, British Columbia, Canada (2004-2006). Environmental Toxicology and Chemistry 29: 1593-1603.

• Read more about this study in the context of environmental testing: Putting Environmental Testing to the Test

Contact: Christine Bishop (604) 940-4671

> Mite species suitable for development of new test method

New research has confirmed a species of oribatid mite as a good candidate for the development of a new standardized toxicology test method to help determine the environmental impacts of pollutants. This is a significant contribution in the creation of a suite of tools to help industry and resource managers in Northern boreal ecozones assess risk, remedial actions and other management decisions.

Oribatid mites are among the most abundant and diverse microarthropod in boreal forest soils. Their activity helps to maintain boreal soil quality, and is important for ecosystem health. Not only is the mite a representative species for boreal zones, its relevance for laboratory use and the relatively good knowledge of its lifecycle make it a suitable candidate for toxicology test development.

Scientists examined how an oribatid mite species performed in 15 different horizons, or soil layers, from reference soils across Canada. They also examined the mites’ response to a toxic substance within the horizons of the soil. Oppia nitens displayed reliable benchmarks of survival and reproduction. The mites survived in all types and layers of soil but their ability to reproduce varied depending on the presence of organic matter.

Identifying the applicability of the mite will help ensure the development of robust scientific tools needed to understand various species’ response to northern industrial activities like forestry, mining, and oil and gas exploration. Standardized toxicological text methods for Oppia nitens are under development.

Plotting the sensitivity and distribution of a diverse range of biota will allow managers to better understand the effects of activities and contaminants on ecosystems, determine acceptable levels of risk in their activities, further inform remedial actions, and lead to better use and protection of soil ecosystems.

Environment Canada scientists have produced a series of ecologically relevant biological test methods for boreal zones to assess contaminant response in earthworms and springtails, as well as tree and understory plant species.

The study was funded by the Government of Canada’s Program of Energy Research and Development:

Princz, J.I., V.M. Behan-Pelletier, R.P. Scroggins and S.D. Siciliano. 2010.  Oribatid mites in soil toxicity testing – the use of Oppia nitens (C.L. Koch) as a new test species.  Environ. Toxicol. Chem. 29: 971-979.

• Read more about biological method development for boreal soils: Protecting Canada’s Boreal Forests and Northern Ecosystems: Developing Biological Methods to Assess and Preserve Canada’s Soil Environments of the North

Contact: Juliska Princz (613) 990-9544

> Developmental effects measured in predatory birds from exposure to flame-retardant chemicals

Dr. Kim Fernie is leading studies to determine the reproductive and developmental effects in predatory birds from exposure to flame-retardants. Captive-raised male American kestrels were exposed in ovo, through the diet of their mothers, to environmentally-relevant levels of the flame-retardant chemical, polybrominated diphenyl ethers (PBDEs). The young birds were then observed and possible changes were recorded relating to their reproductive success, physiology and reproductive behaviours. This appears to be the first effort to determine the multi-generational effects of exposure to several types of flame-retardants in birds. The results may assist in extrapolating potential effects to wild species.

One year following embryonic exposure, the male birds were paired with “chemically-clean” females. Reproductive success was lower in the high-exposure pairs: 43% failed to lay eggs and the others laid smaller clutches and produced smaller eggs with reduced fertility. Typical courtship behaviours were reduced in all exposed males with decreasing trends according to exposure levels in pair-bonding, nest-box behaviours and brood rearing.

The reductions in clutch size and fertility were associated with reduced frequencies of male courtship behaviours, and were associated with increasing concentrations of the flame-retardant chemicals. In addition, the high-exposure males had lower testosterone levels, increased sperm numbers and heavier testes: histological changes were evident and associated with in ovo concentrations of PBDE and individual congeners.

Many flame-retardants are environmentally persistent and bioaccumulative chemical compounds. They are of particular concern to species high on the food web, such as predatory birds. Flame-retardants, including PBDEs, are added to many commercial products, plastics, computers and household materials. The mixture used in the study, the penta-BDE technical mixture DE-71, is no longer in production as of 2006. The DE-71 mixture was used extensively around the world and is comprised of several related chemical congeners: BDE-99 (44%), BDE-47 (38%), BDE-100 (13%) and BDE-153 (5.5%). These are some of the most prominent PBDE congeners found in the environment, wildlife and humans.

This research was conducted by Dr. Fernie’s recent graduate student, Dr. Sarah Marteinson (McGill University). Dr. Fernie’s ongoing research on birds and flame-retardants includes her research on beta-TBECH and hexabromocyclododecane (HBCD), the latter recently added to the Canadian Environmental Protection Act (Schedule 1). Dr. Fernie is an invited expert contributor to the HBCD Draft Risk Profile of the UN Stockholm Convention, the U.S. EPA’s Action Plan on HBCD and to Canada’s Chemicals Management Plan. Her research is made possible through collaborations among scientists at Environment Canada, Fisheries and Oceans Canada and McGill University.

Results were published in Environmental Toxicology and Chemistry:

Marteinson, S.C., Bird, D.M., Shutt, J.L., Letcher, R.J., Ritchie, I.J. and Fernie, K.J. 2010. Multi-generational effects of polybrominated diphenylethers exposure: Embryonic exposure of male American kestrels (Falco sparverius) to DE-71 alters reproductive success and behaviors. Environmental Toxicology and Chemistry 29: 1740–1747. doi: 10.1002/etc.200

A new paper has been accepted by Toxicological Sciences:

Marteinson, S.C., Kimmins, S., Bird, D.M., Shutt, J.L., Letcher, R.J., Ritchie, I.J. and Fernie, K.J. Accepted pending revisions. Embryonic exposure to the polybrominated diphenyl ether mixture, DE-71, affects testes and circulating testosterone concentrations in adult American kestrels (Falco sparverius).

Contact: Kim Fernie (905) 336-4843