David Anthony Kirk

Aquila Conservation & Environment Consulting · Independent Researcher

Mediterranean maquis vegetation is highly biodiverse, but widespread grazing poses a challenge for management and conservation. We sampled woody and herbaceous plants separately on a limestone mountain with strong mesic-xeric gradients in Tunisia’s Parc National de L’Ichkeul, assessed grazing pressure (on a scale of 1–3), and asked whether grazing...

Organic farming is considered beneficial for biodiversity conservation in agricultural landscapes but the role of agricultural land use intensity (‘agricultural intensity’), particularly at regional scales, has often been neglected. We used breeding season bird abundance estimates from paired organic‐conventional fields in Saskatchewan (31 pairs),...

Although farmland birds are used extensively in Europe as an indicator group to assess agricultural impacts on ecosystems, no such group has been formally identified in North America. Here we present a hierarchical framework to identify a suite of farmland bird species in Ontario, Canada by consolidating and validating classifications derived from...

Invasion by generalist tree species can cause biotic homogenization, and such community impoverishment is likely more important in rare forest types. We quantified changes in tree diversity within Carolinian (range in Central Hardwood Forest), central (range in Central Hardwood Forest and Northern Hardwood-Conifer Forest), and northern species [ran...

Grassland birds have undergone widespread global population declines due to loss and degradation of native grasslands. Activities associated with non-renewable energy derived from oil and natural gas extraction have substantially increased on grasslands. The cumulative disturbance generated by natural gas development creates a network of non-linear...

Modelling the distribution and abundance of species at risk is extremely important for their conservation and management. We used ecological niche models (ENMs) to predict the occurrence of western rattlesnakes (Crotalus oreganus) in British Columbia (BC), Canada. We applied this to existing population estimates to support a threshold of occurrence...

Emulating natural disturbance (END) patterns to conserve biodiversity is often a goal of forest management but the impact of forest cutting is still controversial. We examined effects on avian assemblages of partially-cut forest stands of 1–10, 11–20 and>45 years (cut classes) post-harvest differing in the % basal area retained as wildlife species’...

Understanding factors that influence the demography of grassland species in agricultural landscapes is essential given the amount of land under agricultural production. Winter wheat is promoted by avian conservation organizations in North America because it provides cover early in the breeding season without much disturbance to nesting waterfowl. W...

The Northern Pacific Rattlesnake (Crotalus o. oreganus) is restricted in its occurrence in Canada to British Columbia (B.C.) and is listed nationally as a Species-at-risk, yet there is a lack of demographic information, including baseline information on density, survivorship, generation time, and distribution necessary for evaluating the impacts of...

Mediterranean vegetation is characterized by high biodiversity and conservation value and grazing is controversial. We sampled woody and herbaceous plants on a limestone mountain with strong mesic-xeric gradients, ranked grazing pressure (on a scale of 1-4) and asked whether grazing had a significant effect on plant compositional abundance before a...

The concept of the Anthropocene, that humans are now re-engineering global ecosystems, is in part evidenced by the pervasive pollution by persistent organic pollutants (POPs). Certain POPs are hormone mimics and can disrupt endocrine and hence reproductive processes, shown mainly by laboratory studies with model species. There are, in contrast, few...

The foundational concept of habitat lies at the very root of the entire science of ecology, but inaccurate use of the term compromises scientific rigor and communication among scientists and nonscientists. In 1997, Hall, Krausman & Morrison showed that ‘habitat’ was used correctly in only 55% of articles. We ask whether use of the term has been mor...

Organic farming may be more beneficial to biodiversity than nonorganic farming but the comparison is often confounded by regional within-farm and landscape differences. We compared breeding bird species composition and abundance on 10 farm pairs of each type matched at the site level for land cover in the prairie parklands of Saskatchewan, Canada i...

Strychnine is a neurotoxin and an active ingredient in some rodenticides which are placed in burrows to suppress pocket gopher (Thomomys talpoides) populations in range and crop land in western North America. The population level impact was modelled of the use of strychnine-based rodenticides on a non-target snake species, the Great Basin Gophersna...

Forests with old-growth white pines have been severely reduced compared with historical levels. We examined resident and cavity-nesting bird species abundances in winter and the breeding season, because some of these species may prefer old-forest habitats for breeding. We counted birds over 10 years in four mixedwood types: old pine, mature pine, m...

Mercury (Hg) is a global contaminant of aquatic food chains. Aquatic birds, such as the osprey (Pandion haliaetus), with migratory populations breeding in Canada and the northern United States and wintering in the Central and South America, can be exposed to mercury on both the breeding and wintering ranges. We examined Hg levels in 14 fish taxa fr...

Habitat change following forest management may reduce biodiversity in boreal forests, as it has done globally in many forest types. Postharvest silviculture (PHS) is implemented to improve the yield of commercial tree species and has been applied to large areas of boreal forests. PHS may also influence animal communities and so we assessed songbird...

It is now well known that biodiversity in agricultural landscapes can be increased by converting production lands (i.e., farmland) into more natural habitat. However, it remains relatively unknown to what extent biodiversity can also be enhanced by changing the composition and configuration of farmland per se. We examined relationships between farm...

This chapter presents an intercontinental comparison of studies on bird–habitat relationships in three types of cultural landscapes: those created by forestry (managed forests), agriculture (farmed land and remnant native habitats in a matrix of farmed land) and urbanisation. The geographical emphasis is on temperate and boreal regions of eastern C...

We predicted that bird diversity and abundance of some bird species would be higher in old-growth stands than in mature pine stands because of the greater structural diversity in old growth. We also predicted that patch size of stands should be influential. To test these predictions, we modeled counts of 79 bird species from 52 stands in 5 regions...

Many common bird species have declined as a result of agricultural intensification and this could be mitigated by organic farming. We paired sites for habitat and geographical location on organic and nonorganic farms in Ontario, Canada to test a priori predictions of effects on birds overall, 9 guilds and 22 species in relation to candidate models...

Avian Conservation and Ecology Home | Archives | About | Login | Submissions | Subscribe | Contact | Search ACE HOME > VOL. 6, NO. 1 > ART. 5 Copyright © 2011 by the author(s). Published here under license by The Resilience Alliance. Go to the pdf version of this article The following is the established format for referencing this article: Kirk, D...

We examined the distribution of 80 species of breeding birds across 67 census plots from a variety of sources in the boreal forest of western and northern Canada to obtain information on bird habitat associations for forest management. The sites ranged from upland black spruce (Picea mariana) to riverine deciduous forests and wet, marshy bogs. Axis...

We examined the distribution of 80 species of breeding birds across 67 census plots from a variety of sources in the boreal forest of western and northern Canada to obtain information on bird habitat associations for forest management. The sites ranged from upland black spruce (Picea muriana) to riverine deciduous forests and wet, marshy bogs. Axis...

We assessed potential factors contributing to variation in counts of staging Bonaparte’s Gulls (Larus philadelphia) on the Niagara River in southern Ontario. Much of the Mississippi Flyway population of this species stages each autumn at this site, en route to the Gulf coast and Mexico. Between 1986-96, weekly or bi-weekly counts were made of gulls...

Prioritizing new areas for conservation in the Rocky Mountains of North America is important because the current intensity and scale of human development poses an immediate threat to biodiversity. We identified priority areas for avian biodiversity within a 3200-km corridor from Yellowstone National Park in Wyoming, US to the Yukon in Canada (the Y...

We studied the abundance of cavity-nesting birds in forestry-related habitats in a region of Acadian forest in New Brunswick. We examined five reference stands of natural forest, a chronosequence of conifer plantations up to 19 years old (the oldest in the study area), two selectively harvested stands, and a 30-year-old naturally regenerated clear-...

We examined the possibility that granular insecticides, used intensively in the Canadian prairies to control flea beetles (Phyllotreta sp.) in canola (Brassica napus and B. napa), could contribute to bird population declines. A retrospective analysis (1971–96) was done to investigate relationships between counts of 29 bird species made on Breeding...

More than 5 million Canadians take part in recreational angling each year, spending over 50 million days fishing on open water. Recreational anglers contribute to environmental lead deposition through the loss of lead fishing sinkers and jigs. East year lost or discarded fishing sinkers and jigs amounting to an estimated 500 tonnes of lead, and rep...

Population declines of farmland birds over recent decades in Europe, Canada and the USA have been attributed to more intensive agricultural management. We counted birds during the 1990 breeding season on 72 field sites in southern Ontario, Canada, paired between 10 organic and 10 conventional farms for local habitat to enhance our ability to detect...

We made counts of 42 bird species at 217 points in 44 jack pine Pinus banksiana stands in the boreal region of north-central Saskatchewan, Canada because of concerns about the impact of forestry on avian biodiversity. Using multivariate analyses we describe the main patterns of bird species abundance and composition in relation to local habitat var...

Many farmland bird species are declining in North America and Europe, yet there are few data documenting bird use of agricultural landscapes, especially in Canada. This information is needed in order to identify candidate factors contributing to declines. We examined the influence of crop type and adjacent habitat on birds in fields of four crop ty...

Since its first definite sighting in Ontario in 1930. the Little Cull (Larus minuius) has become an uncommon, but increasingly regular, migrant in the Great Lakes region on its way to and from the wintering areas on the Atlantic seaboard and Mississipi River. Over a period of 10 years (1987-1996). Little Gulls and Bonaparte's Gulls (Larus philadelp...

Journal is Ökologie der Vögel

We examined the abundance and distribution of 80 bird species in 101 breeding bird census plots collated from a wide range of sources in the boreal forest of western Canada. In order to examine the relative importance of stand attributes and geographical location we used Canonical Correspondence Analysis (CCA). Two-way indicator species analysis (T...

To assess the factors behind possible global declines in some birds and to investigate the vulnerability of birds to agricultural practices, information is needed on bird use of farmland in much of Canada, including the Mixedwood Plains ecozone of southern Ontario. We examined the pattern of bird use of four crop types in three counties of southern...

The use of cropfields by birds is largely unknown in southern Canada and consequently the risk incurred by pesticide use on bird populations cannot be adequately characterised. The activity patterns and relative interior to edge use of bird species were examined for four crops in southern Ontario to assess the susceptibility of different species to...

We examined population trends and status in 37 taxa of Canadian raptors using Breeding Bird Survey (BBS) data (1966–1994 and 1985–1994) for the whole of Canada and seven ecozones separately, continent-wide Christmas Bird Counts (CBC) (1959–1988), migration counts from 12 hawkwatches (various dates) and specific research projects. According to the p...

We counted breeding birds at four plots in central Saskatchewan and four in western Manitoba in 1990-1992 to examine changes in species composition and abundance since the plots were originally surveyed in 1972 1973. In Saskatchewan, more species of Neotropical migrants decreased (16) than increased (9; P > 0.05 < 0.1). Combined densities of Neotro...

We measured the bones of extinct great auks Pinguinis impennis that were killed during recent centuries on Funk Island off the northeast coast of Newfoundland. Comparisons of these measurements with those taken elsewhere suggest that great auks from Funk Island, which is situated in a Low Arctic oceanographic region, were larger than conspecifics f...

Many bird species consume large quantities of invertebrates, some of which are considered agricultural pests. However, relatively few quantitative studies demonstrate that avian predators can reduce agricultural insect pests below a level at which unchecked populations would cause economic damage to crops or require treatment with pesticides. In fa...

We placed carcasses in three different vegetation types in the heterogeneous savannas of central Venezuela to investigate the role of social dominance in habitat use by flocking migrant and resident turkey vultures (Cathartes aura meridionalis and C. a. ruficollis). Migrants foraged primarily in savanna habitats while residents foraged almost exclu...

We investigated spatial and temporal differences in the habitat associations of five New World vulture taxa (family Vulturidae auct. Cathartidae) in the Llanos of central Venezuela. Overall numbers of vultures were higher over open or semi-open savanna habitats than closed canopy riverine gallery forest. Black Vultures Coragyps atratus brasiliensis...

We investigated seasonal changes in the body condition of migrant and resident Turkey Vultures (Cathartes aura meridionalis and C. a. ruficollis), as well as Black Vultures (Coragyps atratus brasiliensis), in the Llanos of central Venezuela. Although the condition of adult migrants was below average in October and November following migration from...

Hares (Lepus spp.) often occur at high densities in populations on small oceanic islands. We assessed the population size of the introduced black-naped hare Lepus nigricollis nigricollis on Cousin Island (29 ha), Seychelles, Indian Ocean, during the dry season, using mark-recapture techniques. An estimated 128-170 hares occurred on the island, or a...

The habitat use and feeding ecology of the introduced Indian black-naped hare Lepus nigricollis nigricollis (Cuvier) was studied on Cousin Island in the Seychelles with a view to assessing the impact of hares on vegetation and thus indirectly on several rare endemic landbirds and some seabird species. Habitat use was assessed by determining the dis...

I examined the contents of Tawny Owl (Strix aluco sylvatica) pellets, between April 1977 and February 1978, in mixed woodland and gardens in northeast Suffolk, England. Six mammal, 14 bird and 5 invertebrate species were recorded in a sample of 105 pellets. Overall, the Wood Mouse (Apodemusylvaticus) was the most frequently taken mammal prey and th...

BLDSC reference no.: DX204537 Thesis (doctoral)--University of Glasgow, 1988.