Jean-Pierre L. Savard

Biodiversity concepts and urban ecosystems

Abstract The association of biodiversity and urban ecosystems has usually concerned the impact of urbanization on biodiversity. However, biodiversity concepts can easily be applied to the urban ecosystem itself. As more and more people live in cities, restoration, preservation and enhancement of biodiversity in urban areas become important. Concepts related to biodiversity management such as scale, hierarchy, species identity, species values, fragmentation, global approaches can be used to manage urban biodiversity. Application of these concepts in such artificial ecosystems may yield important insights for the management of natural ecosystems. Birds are highly visible and quite sensitive to changes in habitat structure and composition. Bird species richness in urban ecosystems is influenced both by local and landscape characteristics and a multi-scale approach is essential to its proper management. People–wildlife conflicts are an integral component of wildlife management in urban ecosystems and must be addressed. Enhancement of biodiversity in urban ecosystems can have a positive impact on the quality of life and education of urban dwellers and thus facilitate the preservation of biodiversity in natural ecosystems.

Bird abundance and diversity along an urban-rural gradient: A comparative study between two cities on different continents

We compared the avifauna in two cities, Quebec (Canada) and Rennes (France), in order to define general responses of wildlife in an urban ecosystem. These cities have a similar urban structure that permits investigation along an urbanization gradient from downtown to rural residential areas. However, they are in opposite temperate climate and imbedded in a forested and an agricultural landscape, respectively. Plots ranging from 10 to 20 ha were surveyed in winter and spring by recording all birds seen or heard. Most plots could be located along a gradient according to proportions of vegetated open space. Both the Shannon-Wiener and Simpson indices of diversity indicated a pattern of increasing diversity from most to least urbanized areas in spring. Winter species diversity and richness was low in Quebec compared to Rennes, reflecting the much harsher winter conditions in Quebec. Breeding densities of House Sparrows (Passer domesticus) and European Starlings (Sturnus vulgaris) were quite similar in Quebec and Rennes, as were densities of European Blackbirds (Turdus merula) and its ecological equivalent in Quebec, the American Robin (Turdus migratorius). The type of surrounding landscape can not explain the variation of species numbers within the city. If we examine the urban environment as a new ecological system rather than a degraded environment, we can regroup birds in two major species groups: the omnivorous species adapted to the urban environment and its particular food resources such as garbage and the species that find, in the urban environment, resources which they normally exploit in their usual habitat.

LANDSCAPE-SCALE DISTURBANCES AND CHANGES IN BIRD COMMUNITIES OF BOREAL MIXED-WOOD FORESTS

Bird community response to both landscape-scale and local (forest types) changes in forest cover was studied in three boreal mixed-wood forest landscapes modified by different types of disturbances: (1) a pre-industrial landscape where human settlement, agriculture, and logging activities date back to the early 1930s, (2) an industrial timber managed forest, and (3) a forest dominated by natural disturbances. Birds were sampled at 459 sampling stations distributed among the three landscapes. Local habitat and landscape characteristics of the context surrounding each sampling station (500-m and 1-km radius) were also computed. Bird communities were influenced by landscape-scale changes in forest cover. The higher proportion of early-successional habitats in both human-disturbed landscapes resulted in significantly higher abundance of early-successional bird species and generalists. The mean number of mature forest bird species was significantly lower in the industrial and pre-industrial landscapes than in the natural landscape. Landscape-scale conversion of mature forests from mixed-wood to deciduous cover in human-disturbed landscapes was the main cause of changes in mature forest bird communities. In these landscapes, the abundance of species associated with mixed and coniferous forest cover was lower, whereas species that preferred a deciduous cover were more abundant. Variation in bird community composition determined by the landscape context was as important as local habitat conditions, suggesting that predictions on the regional impact of forest management on songbirds with models solely based on local scale factors could be misleading. Patterns of bird species composition were related to several landscape composition variables (proportions of forest types), but not to configuration variables (e.g., interior habitat, amount of edge). Overall, our results indicated that the large-scale conversion of the southern portion of the boreal forest from a mixed to a deciduous cover may be one of the most important threats to the integrity of bird communities in these forest mosaics. Negative effects of changes in bird communities could be attenuated if current forestry practices are modified toward maintaining forest types (deciduous, mixed-wood, and coniferous) at levels similar to those observed under natural disturbances.

SNAG USE BY FORAGING BLACK-BACKED WOODPECKERS (PICOIDES ARCTICUS) IN A RECENTLY BURNED EASTERN BOREAL FOREST

Abstract We studied snag use for foraging by Black-backed Woodpeckers (Picoides arcticus) one year after a fire in an eastern black spruce (Picea mariana) boreal forest in Quebec, Canada. We searched for signs of foraging (bark flaking and excavation holes) by Black-backed Woodpeckers on 6,536 snags sampled in 56 plots located in portions of the burned forest that had not been salvage logged. A logistic regression model was developed based on the presence or absence of foraging signs. Results showed that Black-backed Woodpeckers used larger snags that were less deteriorated by fire (qualified as high-quality snags). Direct field observations of individuals foraging on 119 snags also indicated that used snags corresponded to those of high predicted quality. Finally, we assessed the relationship between food availability and snag characteristics by measuring the density of wood-boring beetle larvae holes on 30 snags of different size and deterioration classes. High-quality snags contained higher prey densities (wood-boring beetle holes) than smaller and more deteriorated snags. We recommend that forest blocks characterized by large and less deteriorated trees be preserved from salvage logging in recently burned boreal forests in northeastern North America.

Changes in breeding bird richness and abundance in Montreal parks over a period of 15 years

We compared the breeding bird population and vegetation structure of 201 randomly selected 1 ha plots in 49 urban parks in Montreal, 15 years apart (in 1979‐1981 and 1994). The constancy of 17 bird species increased significantly, while that of four others decreased. Increased large-tree cover and a reduction in shrub cover do not explain more than a small proportion of this variation in species constancy. We contend that the installation of bird feeder stations in and around parks goes a long way toward explaining these changes, although the recent arrival in Quebec of the House Finch (Carpodacus mexicanus) and the Northern Cardinal (Cardinalis cardinalis) has definitely played a major role in the changes of the bird assemblage. # 1999 Elsevier Science B.V. All rights reserved.

Evidence of Long-Term Pair Bonds in Barrow's Goldeneye (Bucephala islandica)

Geese, swans, and ducks that cooperate in raising young maintain long-term pair bonds (Kear 1970, Bolen 1971, Weller 1976, Patterson 1982). In most holarctic ducks the female raises the young alone, new pairs are formed every year on wintering and/ or migration areas, and males follow their philopatric female to breeding areas (Hochbaum 1944, Rowley 1983, and others). Female Barrows Goldeneye (Bucephala islandica) return to the same breeding area every year and often use the same nesting sites (Palmer 1976). Males accompany their mates from wintering areas, defend territories on the breeding ground, and then leave for unknown molting areas when the female is incubating (Savard 1982). They are not seen again on the breeding ponds until the following spring. I present evidence here indicating that some Barrows Goldeneye pairs remain intact from year to year in spite of a long separation and that pair reunion occurs on the wintering areas. During a study of the breeding ecology of Barrows Goldeneye in central British Columbia, I captured 15 adult drakes and 81 adult females and marked them with nasal disks. The return rate of females to the study area was 77% (n = 36) in 1982 and 75% (n = 81) in 1983, indicating a high degree of site fidelity. Similar rates of return for females have been found in other cavity-nesting ducks (Erskine 1961, Dow 1983). The return rate of drakes was 71% (n = 7) in 1982 and 63% (n = 15) in 1983. Two of three pairs marked in 1982 returned intact in 1983; the other did not return. The females of the two returning pairs had raised a brood in 1982 and therefore were separated from their mates for at least 4 months. The existence of longterm pair bonds was confirmed in 1984, when 3 of 7 marked pairs returned intact. Of the remaining pairs, 1 split and only 1 member returned in the other 3. The 2 females that had lost their mates had repaired when resighted, but the 4 males had not. These 4 males returned to the same pond where they had been captured the previous year, and 1 even defended a territory for 2 days. Usually, unpaired males do not defend territories (Savard 1982). One Barrows Goldeneye drake marked on his territory in 1982 defended the same territory in 1983 and 1984. Similarly, 3 other paired males were resighted on the same territory the following year. Although the females of these males were not marked, it is likely that they retained their previous mates because females apparently select the territory in most territorial waterfowl (Hochbaum 1944, Young 1970, Donaghey 1975). The preceding observations indicate that pairs in Barrows Goldeneye can remain intact from year to year in spite of a long separation and that unpaired males home to their previous breeding area. Homing of unpaired drakes to breeding areas has been reported in several dabbling ducks (Poston 1974, Blohm 1978) and diving ducks (Bengtson 1972, Alison 1975, Donaghey 1975). Breeding philopatry in unpaired males would increase their chances of finding a mate, or of reuniting with a previous mate. It could also enhance their survival because of their familiarity with the resources of the area. I now consider where and how pairs reunite. Within a week of the arrival of Barrows Goldeneye on their wintering areas in southern coastal British Columbia in early November, some pairs are already defending territories (Savard unpubl. data). Of 34 territories defended along a 5-km stretch of shoreline in Burrard Inlet near Vancouver, B.C. in February and March 1983, 59% were occupied by mid-December and 85% by late December. This rapid formation of pairs soon after the arrival on the wintering areas, when there is little courtship, suggests that pairs reunite then. In 1983, 55% of the 400 males present in Burrard Inlet on 17 November had arrived by 1 November, compared to only 11% of the 200 females. This earlier arrival of the males supports the contention that most pairs reunite on the wintering ground rather than on fall staging areas. Spurr and Milne (1976) found similar pair formation in the Common Eider (Somateria mollissima) that also involved little courtship. Butterfield (1970) also observed that pairs of Zebra Finch (Poephila guttata) that reunited after separation displayed little courtship. I was fortunate to document the reunion of one pair of Barrows Goldeneye on the wintering area. A drake marked on his breeding territory in 1982 was resighted near Vancouver, B.C. defending a winter territory at the tip of a small jetty. He was paired with an unmarked female, and they remained in their territory all winter. In April 1983 the male defended the same breeding territory as in 1982. He was paired, presumably with the female with whom he had wintered. We marked her that summer, and she raised a brood while the male departed for the molting grounds. On 29 October we sighted the male in a small group of goldeneye (37 males, 3 females, 10 immatures) 2 km east of his winter territory. Daily checks indicated that he remained there until 12 November. On 8 November we sighted his mate in a large group of goldeneye (84 males, 39 females, 1 immature) 4 km from the location of the male. This coincided with the first big influx of adult females

Evaluating the sustainability of harvest among northern common eiders Somateria mollissima borealis in Greenland and Canada

Sustainable harvest, the extraction of game without affecting population viability, is a desirable approach to the use of wildlife. However, overharvest has been responsible for the decline of many wildlife populations globally, so there is an urgent need to balance human requirements while avoiding the severe depletion of wild populations. Northern common eiders Somateria mollissima borealis are heavily hunted in Canada and Greenland, but the effect of this intensive harvest has not been examined. We developed a population model to investigate the sustainability of the reported harvest, which consisted of two wintering areas in Greenland and Atlantic Canada and three breeding populations. The model indicated that harvest in Atlantic Canada was sustainable, but a number of conditions could lead to slow declines. In contrast, the annual winter harvest of 55,000–70,000 eiders reported during 1993–2000 in Greenland was not sustainable, and this conclusion held under a wide range of alternate conditions. The model indicated that harvest during late winter may have a greater effect on populations than harvest in early winter. We further refined the model to assume that at some low population level the success of hunters would decline and that harvest became a function of population size (a rate). This scenario had the expected and undesirable result of stabilizing populations at very low levels. Overall, our model suggests that the high harvest reported in Greenland during 1993–2000 endangers the sustainable use of the northern common eider population and that management actions are required. Common eider harvest levels in Greenland should be reduced by at least 40% of the 1993–2000 levels to stop projected declines, and allow for recovery of the decimated Greenland breeding population. Encouragingly, new hunting regulations were introduced in Greenland in 2002–2004, and harvest levels appear to be decreasing. If these harvest reductions continue, our population model could be used to re-evaluate the status of populations in the two countries.

RELATIONSHIP AMONG BREEDING, MOLTING, AND WINTERING AREAS OF MALE BARROW'S GOLDENEYES (BUCEPHALA ISLANDICA) IN EASTERN NORTH AMERICA

Abstract Little is known of the eastern North American population of Barrows Goldeneyes (Bucephala islandica), which was recently listed as “of special concern” in Canada. In 1998 and 1999, we marked 18 adult males wintering along the St. Lawrence River, Québec, with satellite transmitters to document their breeding, molting, and wintering distribution and phenology, and to describe timing and routes of their spring, molt, and fall migrations. Thirteen males moved inland from the St. Lawrence River to breed; the spring migration averaged 5.9 days, and birds arrived on breeding areas on average 9 May. All breeding areas were inland, on the north shore of the St. Lawrence River estuary and gulf. Breeding areas averaged 64.8 km from the St. Lawrence corridor. Males stayed on their respective breeding area a mean of 34.5 days, and left on average 11 June. Twelve males were tracked to their molting areas, one of which stayed on its wintering area until 5 June and flew directly to its molting area. Their molt migration averaged 18.6 days, and the mean arrival date on molting areas was 30 June. All molting areas were located north and averaged 986 km from breeding areas. Four males molted in Hudson Bay, four in Ungava Bay, two in northern Labrador, one on Baffin Island, and one inland, near the Québec–Labrador border. The mean length of stay on the molting areas was 105.3 days, and the mean date of departure from molting areas was 4 October. All goldeneyes for which the radio still functioned during fall migration returned to winter in the St. Lawrence River estuary, on average 6 November. Our results refute the idea that the main breeding area of the eastern North American population of Barrows Goldeneyes is located in northern Québec and Labrador and rather indicate that it is in the boreal forest just north of the St. Lawrence River estuary and gulf. They also indicate that Barrows Goldeneye males undertake a genuine molt migration, and highlight the importance of molting areas because birds stayed there approximately four months each year.

Habitat Requirements of Breeding Black-Backed Woodpeckers ( Picoides arcticus ) in Managed, Unburned Boreal Forest

We investigated home-range characteristics and habitat selection by Black-backed Woodpeckers (Picoides arcticus) in an unburned, boreal forest landscape managed by mosaic harvesting in Quebec, Canada. Habitat selection by this species was specifically examined to determine home-range establishment and foraging activities. We hypothesized that Black-backed Woodpeckers would respond to harvesting by adjusting their home-range size as a function of the amount of dead wood available. Twenty-two birds were tracked using radiotelemetry, and reliable estimates of home-range size were obtained for seven breeding individuals (six males and one female). The average home-range size was 151.5 +/- 18.8 ha (range: 100.4-256.4 ha). Our results indicate that this species establishes home ranges in areas where both open and forested habitats are available. However, during foraging activities, individuals preferentially selected areas dominated by old coniferous stands. The study also showed that the spatial distribution of preferred foraging habitat patches influenced space use, with home-range area increasing with the median distance between old coniferous habitat patches available within the landscape. Finally, these data show that Black-backed Woodpeckers may successfully breed in an unburned forest with at least 35m3 • ha-1 of dead wood, of which 42% (15m3• ha-1) is represented by dead wood at the early decay stage. Nous avons etudie les caracteristiques du domaine vital et la selection de l’habitat chez le Pic a dos noir (Picoides arcticus) en foret boreale non brulee et amenagee par coupes en mosaique, au Quebec (Canada). La selection de l’habitat a ete tout particulierement examinee afin de determiner le domaine vital et les activites liees a l’alimentation chez cette espece. Nous avons emis l’hypothese selon laquelle le Pic a dos noir reagirait a la recolte de bois en modifiant la taille de son domaine vital selon la quantite de bois mort accessible. Vingt-deux oiseaux ont ete suivis a l’aide de la telemetrie et des estimations fiables de la taille du domaine vital ont ete obtenues pour sept individus nicheurs (six mâles et une femelle). La taille moyenne du domaine vital a ete evaluee a 151,5 ± 18,8 ha (etendue : 100,4–256,4 ha). Nos resultats indiquent que cette espece etablit son domaine vital la ou des milieux ouverts et des milieux forestiers sont accessibles. Toutefois, au moment de s’alimenter, les individus selectionnent preferablement les endroits ou dominent les peuplements de vieux coniferes. Les travaux ont egalement montre que la repartition spatiale des ilots d’habitat preferes pour l’alimentation du pic influence l’utilisation de l’espace : la taille du domaine vital augmente en fonction de la distance mediane entre les ilots de vieux coniferes accessibles dans le paysage. Enfin, les resultats indiquent que le Pic a dos noir peut nicher avec succes en foret non brulee s’il y a un volume de bois mort d’au moins 35 m3 • ha-1, dont 42 % (15 m3 • ha-1) est en debut de decomposition.

Avian mortalities due to transmission line collisions: a review of current estimates and field methods with an emphasis on applications to the Canadian electric network

Birds are vulnerable to collisions with human-made fixed structures. Despite ongoing development and increases in infrastructure, we have few estimates of the magnitude of collision mortality. We reviewed the existing literature on avian mortality associated with transmission lines and derived an initial estimate for Canada. Estimating mortality from collisions with power lines is challenging due to the lack of studies, especially from sites within Canada, and due to uncertainty about the magnitude of detection biases. Detection of bird collisions with transmission lines varies due to habitat type, species size, and scavenging rates. In addition, birds can be crippled by the impact and subsequently die, although crippling rates are poorly known and rarely incorporated into estimates. We used existing data to derive a range of estimates of avian mortality associated with collisions with transmission lines in Canada by incorporating detection, scavenging, and crippling biases. There are 231,966 km of transmission lines across Canada, mostly in the boreal forest. Mortality estimates ranged from 1 million to 229.5 million birds per year, depending on the bias corrections applied. We consider our most realistic estimate, taking into account variation in risk across Canada, to range from 2.5 million to 25.6 million birds killed per year. Data from multiple studies across Canada and the northern U.S. indicate that the most vulnerable bird groups are (1) waterfowl, (2) grebes, (3) shorebirds, and (4) cranes, which is consistent with other studies. Populations of several groups that are vulnerable to collisions are increasing across Canada (e.g., waterfowl, raptors), which suggests that collision mortality, at current levels, is not limiting population growth. However, there may be impacts on other declining species, such as shorebirds and some species at risk, including Alberta’s Trumpeter Swans (Cygnus buccinator) and western Canada’s endangered Whooping Cranes (Grus americana). Collisions may be more common during migration, which underscores the need to understand impacts across the annual cycle. We emphasize that these estimates are preliminary, especially considering the absence of Canadian studies. RESUME. Les oiseaux sont vulnerables aux collisions avec les structures fixes d’origine anthropique. Malgre le developpement continuel et l’augmentation du nombre d’infrastructures, nous avons peu d’estimations sur l’ampleur de la mortalite par collision. Nous avons procede a une revue de la litterature touchant la mortalite aviaire associee aux lignes de transport d’electricite et avons calcule une estimation preliminaire pour le Canada. L’estimation de la mortalite attribuable aux collisions avec les lignes electriques pose un defi en raison du manque d’etudes, particulierement au Canada, et de l’incertitude quant a l’ampleur des biais dans la detection. La detection des collisions aviaires avec les lignes electriques varie en fonction du type d’habitat, de la taille de l’espece et des taux de disparition des carcasses par les charognards. De plus, les oiseaux peuvent etre blesses a la suite d’une collision et en mourir par la suite, mais les taux de blessures mortelles sont peu connus et rarement inclus dans les estimations. Nous avons utilise des donnees existantes pour calculer differentes estimations de la mortalite aviaire attribuable a ce type de collision au Canada, en incluant les erreurs relatives a la detection, a la predation par les charognards et aux blessures mortelles. Il y a 231 966 km de lignes de transport d’electricite au Canada, surtout situees en foret boreale. Les estimations de la mortalite s’etendaient de 1 a 229,5 millions d’oiseaux par annee, une fois les corrections faites pour tenir compte des erreurs. L’estimation la plus realiste, en tenant compte de la variabilite du risque selon l’endroit au Canada, se situe entre 2,5 et 25,6 millions d’oiseaux morts par annee. D’apres des donnees issues de nombreuses etudes realisees au Canada et dans le nord-est des Etats-Unis, les groupes d’oiseaux les plus vulnerables sont : 1) la sauvagine; 2) les grebes; 3) les limicoles; et 4) les grues. Independent Researcher, Environment Canada Avian Conservation and Ecology 8(2): 7 http://www.ace-eco.org/vol8/iss2/art7/ Les populations de plusieurs groupes d’oiseaux vulnerables aux collisions sont en augmentation au Canada (p. ex. sauvagine, rapaces), ce qui indique que la mortalite attribuable aux collisions, selon les estimations actuelles, ne limite pas la croissance des populations. Toutefois, cette mortalite peut avoir un impact sur d’autres especes en declin, comme les limicoles et certaines especes en peril, y compris le Cygne trompette (Cygnus buccinator) en Alberta et la Grue blanche (Grus americana) dans l’Ouest du Canada, espece en voie de disparition. Il se peut que les collisions soient plus frequentes durant les migrations, ce qui fait ressortir la necessite de bien comprendre les impacts tout au long du cycle annuel. Nous insistons sur le fait que les estimations presentees sont preliminaires, surtout parce qu’il n’y a pas encore d’etudes canadiennes.