Multi-Scale Studies of Populations, Distribution and Habitat Associations of Marbled Murrelets in Clayoquot Sound, British Columbia 1 March 2002 Ministry of Water, Edited by Land and Air Protection Alan E. Burger and Trudy A. Chatwin National Library of Canada Cataloguing in Publication Data Main entry under title: Multi-scale studies of populations, distribution and habitat associations of Marbled Murrelets in Clayoquot Sound, British Columbia Also available on the Internet. Includes bibliographical references : p. ISBN 0-7726-4739-9 1. Marbled murrelet - British Columbia – Clayoquot Sound Region. 2. Marbled murrelet - Habitat - British Columbia – Clayoquot Sound Region. 3. Ecological surveys - British Columbia – Clayoquot Sound Region. I. Burger, Alan E. II. Chatwin, Trudy A. III. British Columbia. Ministry of Water, Land and Air Protection. QL696.C42M84 2002 333.95'833 C2002-960063-4 Multi-Scale Studies of Populations, Distribution and Habitat Associations of Marbled Murrelets in Clayoquot Sound, British Columbia Edited by Alan E. Burger and Trudy A. Chatwin Ministry of Water, Land and Air Protection Victoria, BC March 2002 Table of Contents 1. Introduction and Overview of the Clayoquot Sound Study . 1 Trudy A. Chatwin and Alan E. Burger 2. At-Sea Surveys of Marbled Murrelets in Clayoquot Sound, 1996-2000 . 15 Adrienne Mason, Alan E. Burger and Bob Hansen 3. Radar Inventory and Watershed-level Habitat Associations of Marbled Murrelets in Clayoquot Sound, 1996-1998. 35 Alan E. Burger 4. Inland Activity and Forest Structural Characteristics as Indicators of Marbled Murrelet Nesting Habitat in Clayoquot Sound. 57 Michael S. Rodway and Heidi M. Regehr 5. Can Marbled Murrelet Use of Nesting Habitat be Predicted from Mapped Forest Characteristics?. 89 Volker Bahn and Deanna Newsom 6. Habitat Suitability Mapping for Marbled Murrelets in Clayoquot Sound . 101 Volker Bahn and Deanna Newsom 7. Estimating Nest Densities for Marbled Murrelets in Three Habitat Suitability Categories in the Ursus Valley, Clayoquot Sound. 121 Catherine J. Conroy, Volker Bahn, Michael S. Rodway, Laurie Ainsworth and Deanna Newsom 8. Management of Marbled Murrelet Nesting Habitat in Clayoquot Sound . 139 Trudy A. Chatwin Opinions expressed by the authors in this publication are their own and do not necessarily reflect provincial government policy. i Flores Island west coast. Clayoquot Sound has the combination of rich waters for feeding and intact old-growth forests for nesting Marbled Murrelets. The Clayoquot Sound Scientific Panel for Sustainable Forest Practices provided direction for inventory and planning related to Marbled Murrelets. Their recommendations are based upon the principal of maintenance of ecological integrity. (Trudy Chatwin) ii Introduction and Overview of the Clayoquot Sound Study Introduction and Overview of the Clayoquot Sound Study by Trudy A. Chatwin and Alan E. Burger According to Nuu-chah-nulth elders, the story of dark twilight, before sunrise and after sunset. Most Clayoquot Sound is one of forest and sea. Indeed, the seabirds have black backs and white bellies, which connection between land and water is found throughout provides a form of camouflage on and under the ocean. the natural history of Clayoquot Sound’s multitude of Marbled Murrelets have this plumage in winter and species, from the tiniest invertebrates, fungi and lichens when they fledge as juveniles. When breeding, however, through to the salmon, birds, bears and whales. No bird Marbled Murrelets have a mottled brown plumage that species exemplifies this connection between sea and blends into the forest background, making them almost forest better than a small, rather mysterious seabird, the invisible when sitting quietly on mossy branches or Marbled Murrelet. when flying into the forest. Known or suspected predators of murrelets that are found on Vancouver Marbled Murrelets are unique among seabirds in nesting Island include Steller’s Jay (Cyanocitta stelleri), Gray far inland in old-growth forests. Their coloration, body Jay (Perisoreus canadensis), Northwestern Crow (Corvus form (morphology) and behaviours have evolved in caurinus), Common Raven (Corvus corax), Bald Eagle response to the combination of living in nearshore seas (Haliaeetus leucocephalus), Northern Goshawk and nesting in ancient forests. These adaptations have (Accipiter gentilis), Sharp-shinned Hawk (Accipiter important consequences for their conservation and striatus), Barred Owl (Strix varia), Great-horned Owl management. As a diving seabird that uses its wings (Bubo virginianus), Red Squirrel (Tamiasciurus to “fly” underwater in pursuit of prey, the Marbled hudsonicus) and deer mice (Peromyscus spp.). Murrelet’s wings are small but powerful. Their wing- loading (ratio of body mass to wing area) is among the Marbled Murrelets spend most of their lives in the highest in the bird world. When breeding, they daily fly nearshore waters of the Pacific Ocean, feeding on small to nest sites up to 80 km inland, and can reach speeds marine fish, such as sand lance (Ammodytes hexapterus), of over 120 km/hr. Their high wing-loading means that juvenile Pacific herring (Clupea harengus), northern Marbled Murrelets are not particularly adept at making anchovy (Engraulis mordax) and immature rockfish flying manoeuvres within the complex and dense forest (Sebastes spp.). Large zooplankton, such as euphausiids, canopy where they nest. Their legs are set far back on are also eaten. The complex coast of Clayoquot Sound, the body and they have webbed feet to facilitate diving. with protected bays, long inlets, areas of upwelling off These adaptations make it almost impossible for rocky reefs, and islets on the open west coast, provides murrelets to take off from level ground, and therefore ideal feeding grounds for murrelets. they need to find an elevated platform for nesting. In most cases this platform is a broad, mossy limb high Just as importantly, undisturbed areas of temperate above the ground in an old-growth tree, but occasionally rainforest provide nesting opportunities for murrelets they use mossy ledges on cliffs. on the large, moss-laden boughs of Sitka spruce (Picea sitchensis), western hemlock (Tsuga heterophylla), As long-lived birds with low reproductive capability, western redcedar (Thuja plicata) and amabilis fir (Abies Marbled Murrelets are particularly sensitive to predation amabilis). Clayoquot Sound, despite its history of and show many adaptations for reducing predation. Their conflict over industrial logging, still has large tracts of nests are widely dispersed, making them difficult for undisturbed forests, especially in the Megin, Moyeha, predators to locate. They fly silently to their nests in the Sydney, Clayoquot, Bulson, Ursus and Watta watersheds. Three of the six undisturbed watersheds larger than 5,000 ha on Vancouver Island are in this area (Moore Trudy A. Chatwin1 and Alan E. Burger2 1991). By contrast, much of the Bedwell, Boat Basin, 1Ministry of Water, Land and Air Protection, Cypre, Kennedy and Hesquiaht valleys have been Vancouver Island Region, 2080 Labieux Road, heavily logged, and the Atleo, Tofino Creek, lower Nanaimo, BC, V9T 6J9. Tranquil, and Bedingfield areas have been patchily [email protected] logged. The abundance of forest habitat and the variety 2Department of Biology, University of Victoria, of cutting patterns in Clayoquot Sound provide an Victoria, BC, V8W 3N5. unparalleled area for studying the habitat associations [email protected] of Marbled Murrelets. 1 Chapter 1 History of Marbled Murrelet Studies is interconnected), with ecosystem and cultural values in Clayoquot Sound to be determined and evaluated first. Timber harvesting values were to be considered second, with harvest areas Quantitative research on the murrelet in Clayoquot designated only after ecological and cultural reserves Sound began in 1982 when Harry Carter and Spencer had been designated. This ecosystem-based planning Sealy undertook an at-sea census that covered most of was a paradigm shift from the forest practices of the day, the water from Ucluelet to Estevan Point (Sealy and in which timber extraction targets were set first, and Carter 1984). They estimated a minimum population of environment officials struggled to protect resources by 4,500 murrelets on the water during the breeding season. attempting to modify logging plans. The provincial John Kelson and co-workers subsequently repeated these government accepted all of the Clayoquot Sound counts in 1992, 1993 and 1996, but reported only 2,704, Scientific Panel’s recommendations, and in early 1996 2,622 and 2,901 murrelets in each year, respectively the Clayoquot Planning Team was charged with (Kelson et al. 1995, Kelson and Mather 1999). This implementing the recommendations. decline since 1982 was attributed to loss of nesting habitat due to logging (Kelson et al. 1995), although The BC government’s commitment to meet the Burger (2000) suggested that negative responses by Scientific Panel recommendations, combined with the murrelets to warm ocean conditions in the 1990s might identification of the Marbled Murrelet as a priority also have been a factor. management species, provided the impetus for our studies (see Box 1). At the time of the protests, the Inland, pilot audio-visual surveys were done at 16 Marbled Murrelet was seldom mentioned. When the stations in Clayoquot Sound in 1991 (Savard and Lemon Ursus Valley was designated as a Wildlife Management 1994). In 1993, Irene Manley, John Kelson, Stephanie Zone,