Ross G. Vennesland

Environment Canada | EC · Canadian Wildlife Service

The nesting behaviour of the Great Blue Heron (Ardea herodias L., 1758) was studied in western Canada in 1998 and 1999 to (i)investigate how individual parents assess risk when repeatedly exposed to a disturbance stimulus (an investigator) and (ii)experimentally test in the field whether any variation in their nest defense behaviour was due to expe...

Surveys were conducted at 35 Great Blue Heron (Ardea herodias) colonies in urban and rural landscapes of south-coastal British Columbia, Canada, to investigate low nesting productivity during 1998 and 1999 compared to a decade ago. Nesting failure was common (59% of 1,247 nests) and widespread (in 90% of 31 colonies) and accounted for 96% of the va...

Introduction Up to nine subspecies have been recognized by past researchers, based on differences in plumage color and morphology. Researchers have agreed that Florida‘s Great White Heron (A. h. occidentalis), the subspecies most distinctive in color (entirely white), and the Pacific Great Blue Heron (A. h. fannini) are distinct subspecies. Recent...

In the next century, wading birds will have to deal with the cumulative impact of climate change, human population growth, and the recovery of avian predators. Conservation areas, established under former climate conditions and when there were fewer people and predators, might be inadequate to maintain wading bird populations in the future. We asse...

Abstract Throughout history, humans have settled in areas of high biodiversity. Today these areas are home to our biggest urban centers with biodiversity at increasing risk from escalating cumulative threats. Identifying the management strategies to conserve species within such regions, and ensuring effective governance to oversee their implementat...

This paper analyzes data from two studies that have compared the availability of suitable foraging habitat in known occupied home ranges compared to random locations where occupancy is not known.

Using radiotelemetry we determined for a managed landscape, seasonal home-range sizes and habitat compositions of the threatened Haida Gwaii subspecies of the Northern Saw-whet Owl (Aegolius acadicus brooksi). We trapped 17 owls, and successfully monitored seven: four adult males from May-June 2011 (spring) and three owls (adult male, juvenile male...

Habitat loss due to human development is a threat to colonial waterbird species, which require nesting habitat in proximity to productive aquatic foraging areas to ensure reproductive success. When development of habitat occurs, waterbirds must either tolerate the changes or relocate nesting colonies to habitat elsewhere. Land cover and nesting col...

Fish Traps Threaten Pacific Water Shrew Recovery Kym Welstead and Ross Vennesland The Pacific Water Shrew Recovery Team has learned of several water shrews being killed in minnow traps during fisheries surveys. The many fisheries-related studies on the South Coast of British Columbia could therefore threaten this species at risk. The objectives o...

His tor i cal data on the number of nests and nesting success for 242 Great Blue Heron colonies in British Columbia from 1920 through 1999 were compiled. The meth od ol o gies for data col lec tion differed over the years. We have developed and applied a standard meth od ol ogy for col -lect ing and inter pret ing nesting data to provide con sis te...

Pink sand-verbena, Abronia umbellata, is an endangered plant found at only a handful of sites in coastal sandy beach and dune ecosystems from Baja California to southern British Columbia. Threats include demographic collapse, habitat alteration and disturbance, and invasive species. In Canada, pink sand-verbena is known from just three localities,...