Progress 10/01/05 to 09/30/10

Outputs
OUTPUTS: Project #1. Behavioral and Physiological Differences in Migratory Strategies of a Long-distance Migrant, the Blackpoll Warbler, and a Facultative Short-distance Migrant, the Yellow-rumped Warbler. The work focused on the behavioral and endocrine aspects of migration physiology (i.e. hyperphagia, fattening, and restlessness) and how variation in these processes may reflect different migration strategies. Multiple manuscripts resulted from this project and these, as well as presentations at meetings, have been targeted to the appropriate national and international journals as well as talks to local agencies and societies. A significant amount of information collected during this project has been incorporated into the species account for the Blackpoll and Yellow-rumped warblers in the Cornell Lab of Ornithology/American Ornithologists' Union sponsored Birds of North America online (http://bna.birds.cornell.edu/bna/) resource for life histories of birds and "Birdlife of the Churchill Region: Status, History, Biology" by JR Jehl, Jr., 2004. Trafford Publ. Co. Project #2. Proximate Indicators of the Effects of Forestry Practices on Landbird Survivorship and Reproduction in Maine: The major objectives of this project were to measure hormonal and behavioral aspects of energy regulation and breeding success in landbirds inhabiting different forest stand types at the Penobscot Experimental Forest (PEF) in Bradley, Maine to provide forest managers with information that may help them balance the needs of Maine's forest industry with those of its landbird populations. The results have been provided in reports to forest managers, presented at national meetings, published in appropriate journals, and were the basis for a doctoral dissertation by Dr. J. Johnston, now faculty at UMPI. Project #3. The Laboratory of Avian Biology's Pocket Checklist of Maine's Forest Birds - Birds of the Penobscot Experimental Forest/Maine University Forest. The LAB Pocket Checklist is available on the LAB webpages in a downloadable format. Project #4. The Laboratory of Avian Ecophysiology Database. This large ecophysiological database, now comprising data from over 4,000 individuals, was to have been set up in a searchable on-line database during early 2010 but funds were not available to do so. Project #5. What Factors Constrain Individual Breeding Success and Population Viability in Seabirds of the Gulf of Maine We are integrating ecology, physiology, and behavior in an approach to understand the factors influencing population regulation of several seabird species (Arctic and Common terns, Atlantic Puffin, Razorbill) on managed islands in the Gulf of Maine. This work is in collaboration with USFWS and Univ. of New Brunswick and is used to develop management plans for these species. The work has resulted in one master's thesis (Steven Agius), several reports to respective agencies, and multiple presentations at national and international meetings. The results spurred the development of a more extensive project in alcids at Machias Seal Island, in collaboration with A. Diamond at Univ. of New Brunswick. PARTICIPANTS: Individuals who have worked on these projects for this reporting period: 1. Mr. Wesley Wright - MAFES research assistant, School of Biology and Ecology, University of Maine 2. graduate students: - Evan Adams, PhD, in progress - Adrienne Leppold, PhD, in progress - Kristen Covino, MS, completed 2008 - Stephen Agius, MS, completed 2008 3. Undergraduate Research Experience - Kayla Pelletier, 4. Partner Organizations and collaborators: - Linda Welch, refuge biologist, US F & W, Maine Coastal Islands National Wildlife Refuge, Milbridge, ME - Dr. A.W. Diamond, Professor, Univ. of New Brunswick, Dr. Keith Hobson, Environment Canada, Canadian Wildlife Service. TARGET AUDIENCES: Results of these research projects are shared with the relevant state and federal resource management agencies. More than a dozen presentations from these studies have been made at national and international professional meetings (American Ornithologists Union, Society for Integrative and Comparative Biology) as contributed and invited symposia papers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Short-term outcomes - change in knowledge: - Project #1: increased understanding of how migratory bird populations are regulated throughout the annual cycle. - Project #2: better understanding of how food availability, which can vary spatially and temporally across stands representing different forest harvest practices, influences how well breeding birds regulate their energy demand and how it influences breeding success. - Project #3: the general public's knowledge and appreciation of birds in the several local forests is supported by greater availability of checklists that can be used to help them keep track of what birds can be seen in the area. - Project #4: better research development through information sharing via the on-line database of eco-physiological metrics in a wide variety of birds. - Project #5: increased recognition of sources of variation in adult energetic condition, and the potential impacts on population regulation in several species of seabirds breeding on managed islands in the Gulf of Maine. Medium-term Outcomes - change in action - Development, by state and federal agencies (Maine's DEP and DOC, USF&W, ME Inland Fisheries & Wildlife), of long-term resource management plans that utilize a seasonal interactions framework for songbird, shorebird, and seabirds in the region. Long-term Outcomes - change in condition - Protection of key migratory flyways and associated stopover sites along the Maine coastal and offshore islands. - Continued management and achieved recovery goals by agencies through the protection of seabird habitats throughout the annual cycle - Continued growth of resource-based ecotourism and public appreciation of Maine's wildlife - Achievement of a balance between responsible economic development and resource conservation - Increased quality in research design and reduction of unnecessary data collection (minimizing # animals needed) through access to existing data for variables of interest in a wide variety of bird species.

Publications

• Angelier, F., Holberton, R.L. and Marra, P.P. 2009. Does stress response predict return rate in a migratory bird species: A study of American redstarts and their non-breeding habitat. Proceedings of the Royal Society B: Biological Sciences 276: 3545-3551 (doi: 10.1098/rspb.2009.0868)
• Angelier, F., Holberton, R.L. and Marra, P.P. 2009. How to capture wild passerine species to study baseline corticosterone levels. J. Ornithology (DOI 10.1007/s10336-009-0471-6)
• *Covino, K.M. & Holberton, R.L. 2011. The influence of energetic condition on flight initiation and orientation of migratory songbirds in the Gulf of Maine region. The Auk: in press.
• Publications not reported previously: * Angelier, F., Ballentine, B. Holberton, R.L., Marra, P.P. and Greenberg, R. 2011. What drives variation in the corticosterone stress response between subspecies: a common garden experiment of Swamp sparrows (Melospiza georgiana). J. Evolutionary Biology: in press.

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Project #1. Behavioral and Physiological Differences in Migratory Strategies of a Long-distance Migrant, the Blackpoll Warbler, and a Facultative Short-distance Migrant, the Yellow-rumped Warbler. The work focused on the behavioral and endocrine aspects of migration physiology (i.e. hyperphagia, fattening, and restlessness) and how variation in these processes may reflect different migration strategies. Multiple manuscripts resulted from this project and these, as well as presentations at meetings, have been targeted to the appropriate national and international journals as well as talks to local agencies and societies. Project #2: Proximate Indicators of the Effects of Forestry Practices on Landbird Survivorship and Reproduction in Maine:The major objectives of this project were to measure hormonal and behavioral aspects of energy regulation and breeding success in landbirds inhabiting different forest stand types at the Penobscot Experimental Forest (PEF) in Bradley, Maine to provide forest managers with information that may help them balance the needs of Maine's forest industry with those of its landbird populations. The results have been provided in reports to forest managers and published in appropriate journals. Project #3: The Laboratory of Avian Biology's Pocket Checklist of Maine's Forest Birds - Birds of the Penobscot Experimental Forest/Maine University Forest. The LAB Pocket Checklist was distributed during the national annual meeting of the Association of Field Ornithologists' hosted at UMaine in 2007, and is available on the LAB webpages (in revision) in a downloadable format. Project #4: The Laboratory of Avian Ecophysiology Database. This large ecophysiological database, now comprising data from over 4,000 individuals, is being developed as an online searchable database to help other researchers streamline their research. Project #5: What factors constrain individual breeding success and population viability in seabirds of the Gulf of Maine We are integrating ecology, physiology, and behavior in an approach to understand the factors influencing population regulation of several seabird species (Arctic and Common terns, Atlantic Puffin, Razorbill) on managed islands in the Gulf of Maine. This work is in collaboration with US Fish & Wildlife and University of New Brunswick and is used to develop management plans for these species. PARTICIPANTS: Individuals who have worked on these projects for the reporting period: 1. Mr. Wesley Wright - MAFES research assistant, School of Biology and Ecology, University of Maine 2. graduate students: - Evan Adams, PhD, in progress - Adrienne Leppold, PhD, in progress - Kristen Covino, MS, completed 2008 - Stephen Agius, MS, completed 2008 3. undergraduate research and Honor's thesis projects: - Kristi Kennedy (2008-9) Undergraduate Research Experience - Mellissa Kiermann (2008-9) Undergraduate Research Experience - Kayla Porcelli (2008-9) Undergraduate Research Experience 4. Partner Organizations and collaborators: - Linda Welch, refuge biologist, US F & W, Maine Coastal Islands National Wildlife Refuge, Milbridge, ME - Dr. A.W. Diamond, Professor, Univ. of New Brunswick TARGET AUDIENCES: Results of these research projects are shared with the relevant state and federal resource management agencies. More than a dozen presentations from these studies have been made at national and international professional meetings (American Ornithologists Union, Society for Integrative and Comparative Biology) as contributed and invited symposia papers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Short-term outcomes - change in knowledge: - Project #1: increased understanding of how migratory bird populations are regulated throughout the annual cycle. - Project #2: better understanding of how food availability, which can vary spatially and temporally across stands representing different forest harvest practices, influences how well breeding birds regulate their energy demand and how it influences breeding success. - Project #3: the general public's knowledge and appreciation of birds in the several local forests is supported by greater availability of checklists that can be used to help them keep track of what birds can be seen in the area. - Project #4: better research development through information sharing via the on-line database of eco-physiological metrics in a wide variety of birds. - Project #5: increased recognition of sources of variation in adult energetic condition, and the potential impacts on population regulation in several species of seabirds breeding on managed islands in the Gulf of Maine. Medium-term Outcomes - change in action - Development, by state and federal agencies (Maine's DEP and DOC, USF&W, ME Inland Fisheries & Wildlife), of long-term resource management plans that utilize a seasonal interactions framework for songbird, shorebird, and seabirds in the region. Long-term Outcomes - change in condition - Protection of key migratory flyways and associated stopover sites along the Maine coastal and offshore islands. - Continued management and achieved recovery goals by agencies through the protection of seabird habitats throughout the annual cycle - Continued growth of resource-based ecotourism and public appreciation of Maine's wildlife - Achievement of a balance between responsible economic development and resource conservation - Increased quality in research design and reduction of unnecessary data collection (minimizing # animals needed) through access to existing data for variables of interest in a wide variety of bird species.

Publications

• *Johnston, J.C. and Holberton, R.L. 2009. Forest management and temporal effects on food availability for a ground-foraging bird (Catharus guttatus). Forest Ecology and Management 258:1516-1527.
• *Horton, B.M. and Holberton, R.L. 2009. Corticosterone manipulations alter morph-specific nestling provisioning behavior in male white-throated sparrows (Zonotrichia albicollis). Hormones and Behavior: 56:510-518.
• *Horton, B.M. & Holberton, R.L. 2010. Morph-specific variation in baseline corticosterone and the adrenocortical response in breeding white-throated sparrows (Zonotrichia albicollis). The Auk: accepted, in press.
• *Covino, K.M. & Holberton, R.L. 2010. The influence of energetic condition on flight initiation and orientation of migratory songbirds in the Gulf of Maine region. The Auk: in review.
• *Agius, S. A., Holberton, R.L. and Welch, L. 2010. Differences in migration strategies and pre-breeding condition may explain differences in productivity between Arctic and Common terns breeding at Petit Manan Island in the Gulf of Maine. in revision
• *Holberton, R.L., Diamond, A.W. 2010. Variation in capture method reveals significant variation in adult pre-breeding condition in Atlantic Puffins and Razorbills breeding at Machias Seal Island. in preparation.

Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Project #1. How do migrants meet their energy demand We are studying two species (Blackpoll warbler and Yellow-rumped warbler) with different migration strategies. In 2007, one doctoral dissertation was completed (Jennifer Long), another initiated (Evan Adams). Hormone, metabolite, and stable isotope samples (as indicators of breeding ground origins) were collected at sites in ME (Schoodic Point, Appledore Island), MA (Manomet Bird Observatory, Harvard Forest), PA (Powdermill Nature Reserve), and New Brunswick. Funding was secured from the Churchill Northern Studies Centre for work at Churchill, May-June, 2008. 2009 activities on this project include work at Churchill and the Bartlett Exp'l Forest in New Hampshire. Several manuscripts are in progress; papers have been given at national and international ornithological meetings, symposia, and workshops. Project #2: How do Maine's Forestry Practices Influence Landbird Survivorship and Reproduction. This project resulted in two doctoral dissertations in 2007 (Brent Horton and Jason Johnston). Johnston's work directly linked forestry practices represented at the Penobscot Experimental Forest (PEF) in Bradley, Maine, with Hermit thrush reproductive success. Habitat quality, via food availability, played a major role in influencing adult body condition and nesting success. Horton focused on the endocrine basis of parental care in White-throated sparrows at the PEF. Several publications are in review or are published; the work was presented at national and international meetings. Project #3: How do migrant landbirds use Maine's resources This study took place at Schoodic Point and on Appledore Island and was completed in 2008 as a master's thesis by Kristen Covino. Covino found that migratory songbirds negotiate the coastal areas and islands in the Gulf of Maine based on their energy reserves. Birds in poorer condition move inland away from "riskier" habitats along the coast while birds with ample reserves move along the coast in a more direct and seasonally appropriate direction. This study illustrated the need to identify migrant habitat use in the face of increased pressures to seek alternative energy sources (e.g. wind) along Maine's landscape, particularly as a great number of breeding birds in Ontario, Quebec, and the maritime provinces move through the state on migration. Results were presented at national meetings, to local birding and conservation groups, and to students in science education programs (Schoodic Education and Research Center). Project #4: What factors influence seabird breeding success in the Gulf of Maine In collaboration with the United States Fish and Wildlife Service at Petit Manan Wildlife Refuge in Millbridge, ME, this work focused on how prebreeding condition (hormones, metabolites, immune function) influences breeding success in several species, including the endangered Arctic tern. One master's thesis (Stephen Agius) will be completed Dec. 2008. Results were presented at regional and national meetings, at the annual Gulf of Maine Seabird Working Group meeting, and to local birding and conservation groups. PARTICIPANTS: Doctoral dissertations completed on these projects (2007-8): 1. Dr. Jason Johnston - currently Asst. Professor, UM Presque Isle 2. Dr. Brent Horton - currently Post-doctoral Fellow, Smithsonian Institute 3. Dr. Jennifer Long - currently Asst. Professor, Husson College Master's thesis completed on these projects (2007-8): 1. Kristen Covino - currently biology instructor, Husson College 2. Stephen Agius (to be completed Dec., 2008) Doctoral dissertations initiated on these projects (2007-8) 1. Evan Adams 2. Christopher Tonra Master's thesis initiated on these projects (2007-8): 1. Adrienne Leppold Undergraduate Research supported on these projects (2007-8): 1. Kayla Porcelli 2. Doug Perez 3. Mellissa Kiermann 4. Kristi Kennedy Research Assistant: Wesley Wright Collaborators: 1. Linda Welch, Biologist, USF&W, Millbridge, ME 2. Dr. Antony Diamond, Univ. New Brunswick 3. Dr. Peter Marra, Smithsonian Migratory Bird Center 4. Lynda Leppert, LLL Associates 5. Kevin Fraser, Univ. New Brunswick TARGET AUDIENCES: The work from all of these activities has been presented to local and national audiences (public and professional) including Maine Audubon, American Ornithologists' Union meeting, Association of Field Ornithologists, Wilson Ornithological Society, MIGRATE Workshop PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Basic and applied research into the behavioral, ecological, and physiological aspects of habitat use will provide a better understanding about how animals meet their physiological requirements during different life history stages. Plasma hormones, energy metabolites, and immune function, as measures of body condition, taken throughout different stages of the annual cycle in several species of migrant and resident landbird and seabird species provide insight into how environmental factors such as habitat quality and food availability influence breeding and overwintering success. The results from these studies reveal the physiological basis of different life history strategies and the factors affecting breeding and survival, and underscore the importance of seasonal interactions, i.e. that events during one stage of the annual cycle are not independent of other stages. Songbirds do not respond equally to forest habitats resulting from different management regimes. For many seabirds, resources before, as well as during, breeding are critical to population productivity. Finally, the approach of investigating the physiological underpinnings of seasonal interactions can identify where best, during the life cycle of birds, to direct resources and conservation efforts more efficiently.

Publications

• No publications reported this period

Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: the space alloted for this section is too short - not all of the activities can be outlined here. One doctoral dissertation on the cellular basis of migratory fattening was successfully completed in summer, 2007 (Jennifer Long). Migrants were sampled for plasma corticosterone, metabolites, and/or stable isotope signatures at several sites in New England (Schoodic Point and Appledore Island, and at the Harvard Forest in Petersham, MA. Feather isotope samples were collected to look at breeding ground origin. One new doctoral student, Evan Adams, is focusing on migratory ecophysiology of Blackpoll warblers. We submitted a grant to the Churchill Northern Studies Centre in Churchill, Manitoba, to begin his field work there in 2008. A comparable study site is being investigated in Alaska and the Canadian Maritime provinces to investigate the basis of why some populations are experiencing rapid and extreme population declines in the breeding area and others are not. External funding was received by the National Science Foundation: "Physiological Ecology of Seasonal Interactions: How Do Wintering Ground Events Constrain Breeding Success in Neotropical Migrants?" $225,123.00 for 2007-2019, R. L. Holberton, PI). In 2007, American redstarts (Setophaga ruticilla) were sampled on the wintering grounds in Jamaica, West Indies, and on the breeding grounds at the Queen's University Biological Station in Ontario, Canada. This project aims to link winter habitat quality with subsequent breeding success, and to reveal the underlying physiological mechanisms of carry over effects from winter to the breeding grounds. Results of these projects have been presented at an international symposium on birds and climate change: (2006) Seasonal Interactions in Migratory Birds: Finding the Links Between Carry-Over Effects, Population Regulation, and Environmental Change. ESF - E-BIRD Workshop on Climate Change, Glasgow, Scotland, November, 2006 (R. Holberton, presenter; P.P. Marra, co-author) and at national meetings: (2007) "The Role of Food Availability in Driving Physiological Carry-over Effects from the Non-breeding to the Breeding Season" Association of Field Ornithologists' Mtg., Orono, ME, Peter P. Marra, co-author (2007) "The Role of Food Availability in Driving Physiological Carry-over Effects from the Non-breeding to the Breeding Season" Wilson Ornithologists' Society Mtg., Boston, MA, Peter P. Marra, co-author (2006) "A possible role of corticosterone in mediating transitions from migration to breeding in male White-throated Sparrows". Society of Integrative and Comparative Biology Conference. B. M. Horton, J. A. Long, co-authors These projects have also been featured in several outreach programs such as the NSF's K-12 program that seeks to develop stronger science - based programs in the K-12 school systems and four invited seminars were given during the period. Data analyses continue on all of the projects. PARTICIPANTS: Rebecca Holberton Co-PI: Peter Marra, Smithsonian Migratory Bird Center and National Zoo, Washington, DC Doctoral Students: Jennifer Long, Brent Horton, Jason Johnston, Christopher Tonra, Evan Adams Master's students: Sarah Wilder, Stephen Agius, Kristen Covino Partner organizations and collaborators: Scott McWilliams, Univ. of Rhode Island Joseph Wunderle, U.S. Forest Service Antony Diamond, Univ. of New Brunswick, ATWERN Alex Bond, Univ. of New Brunswick Stephen Kress, National Audubon Society James Baird (retired), Mass. Audubon Linda Welch, U.S. Fish & Wildlife Maine Inland Fisheries and Wildlife Canadian Wildlife Service These projects have supported and continue to support: - five doctoral dissertations (Long, Horton, Johnston = all completed in 2007) - three master's students (Wilder - completed 2007, Agius and Covino - expected completion spring 2007) several undergraduates have completed honors or independent research on these projects. TARGET AUDIENCES: professionals in the field of ornithology, wildlife, resource management, physiology, behavior, ecology of birds. I attend many professional meetings and do many outreach activities. I give many presentations to the public, local interest groups, etc. These projects have supported several NSF GK-12 programs. PROJECT MODIFICATIONS: none

Impacts
Project #1.Migratory songbirds must elevate baseline corticosterone.This response promotes migratory fattening by stimulating hepatic fatty acid synthase activity resulting in the production and storage of energy-rich lipids. Many migrants prepare for breeding well before they reach the wintering grounds, but food limitation during spring migration forces migrants to delay breeding readiness en route in order to allocate energy towards migration. Project #2.Hermit Thrushes rely extensively on fat during the breeding period. Food availability varied temporally and spatially.Spiders, ants, and total invertebrates in general, declined after mid June.This decline may contribute to the decline in clutch size or fledging success in passerine birds.Nests initiated earlier in the season more often consisted of four eggs, whereas nests initiated later in the season more often had three.Spider abundance may contribute to it as spiders were fed extensively to nestlings. Adults supplemented during nestling provisioning did not differ in fat compared to control birds but triglycerides and glycerol of birds with some fat were higher in controls than in food-supplemented birds.While there was no clear relationship between forest management type and forest floor food availability during breeding, effects of forest management type were observed. Birds with some fat and supplemented during provisioning maintained lower glycerol levels, suggesting that they were relying less on fat stores than control birds. Higher glycerol in pre-breeding males captured in selection cuts indicated lower food availability there. During breeding, females had higher glycerol levels in even-age regeneration compared to selection plots and also carried more fat suggesting that these females may be food-limited. In addition to effects on adults, habitat-type influenced pre-fledging nestling mass: 9-day old nestlings from even-age regeneration habitats were lower in mass than those in shelterwood habitats. Project #3: During autumn migration birds in poorer energetic condition were risk-averse, orienting away from the coast where resources and environmental conditions may be more predictable, but add distance to their migration by doing so. In contrast, those with more fat oriented SSW, a direction that minimized time and distance in spite of the greater stochastic nature of the resources along the coastline. Migratory pathways in the Gulf of Maine region are not random: flyways may depend on the birds' ability to maintain optimal body condition. These findings may have implications for land use issues in Maine. Project #4: Arctic terns arrive at Petit Manan Island in poorer body condition than Common terns. Common terns can increase energy reserves in preparation for breeding and maintain them throughout the breeding period while Arctic terns may not, which may explain why Arctic terns on Petit Manan have lower productivity than do Common terns. Thus, pre-breeding events, perhaps as a consequence of the longer migrations of Arctic terns, can influence breeding success.

Publications

• Holberton, R.L., Boswell, T., and Hunter, M.J. 2008. Circulating prolactin and corticosterone concentrations during the development of migratory condition in the Dark-eyed Junco, Junco hyemalis. General and Comparative Endocrinology
• Holberton, R.L., Wilson, C.M., Hunter, M.J., Cash, W.B. and Sims, C.G. 2007. The role of corticosterone in supporting migratory lipogenesis of the Dark-eyed Junco, Junco hyemalis: A model for central and peripheral regulation. Physiological and Biochemical Zoology 80:125-137
• Perkins, D.E. and Holberton, R.L. 2006. Indicators of body condition, energy demand, and breeding success in the Ruddy Turnstone, Arenaria interpres, a species of concern. In Waterbirds Around the World. Eds. G.C. Boere, C.A. Galbraith, and D. A. Stroud. The Stationery Office, Edinburgh, UK. Pp. 551-552.
• Horton, B.M., Long, J.A. and Holberton, R.L. 2007. Intraperitoneal delivery of exogenous corticosterone via osmotic pump in a passerine bird. General and Comparative Endocrinology: 152:8-13.

Progress 10/01/05 to 09/30/06

Outputs
Project #1. We are studying two species, Blackpoll and Yellow-rumped warbler, with extremely different migration strategies, looking for within and between-species differences in corticosterone, lipogenic enzyme regulation, and plasma metabolites of lipogenesis (e.g., triglycerides) before and during migratory fattening. Departure motivation and direction is measured in activity cages and release tests. Results to date: During the overland stage of migration, Blackpolls and Yellow-rumps are identical in how they regulate their energy reserves, but diverge dramatically in their physiology with their respective shifts in migratory behavior, illustrating how selection has acted on physiology to result in divergent sets of behaviors. Flight tunnel trials will be completed over the next few years. Project #2: How do Maine's Forestry Practices Influence Landbird Survivorship and Reproduction? We measure hormonal and behavioral aspects of energy regulation and breeding success in resident and migratory landbirds inhabiting different forest stand types at the Penobscot Experimental Forest (PEF) in Bradley, Maine. Using the Hermit thrush as a model migrant and the Black-capped chickadee as the model resident, we measure gonadal and adrenal hormone levels, metabolite levels of fattening and energy mobilization, and immune function, and ask how these relate to changes in energy demand. We manipulate food availability to look for the effect of territory quality on Hermit thrush breeding success, nestling growth, and adult condition. Current status: Most of the work with Hermit thrush is complete. Several manuscripts have been prepared. Work with chickadees is ongoing. Project #3: How do migrant landbirds use Maine's landscape? Movement of free-living migrants across the Gulf of Maine region is being determined through orientation trials and using mobile marine surveillance radar. Current status: During autumn, 2006, approx. 100 migrant songbirds were captured on migration at Schoodic Point, sampled for several measures of energy regulation, and tested in caged and free-flight trials for their preferred orientation direction to look at how energy reserves influence the way migrants use the Gulf of Maine landscape. Data analyses is underway. A second season is planned for 2007. The mobile radar unit is set up and will be used during the 2007 migration seasons. Project #4: What factors influence breeding success of seabirds breeding in the Gulf of Maine? In collaboration with the USF & W and ME IF&W, we are looking at how prebreeding condition (hormones, metabolites, immune function) influences breeding success in Arctic and Common terns. Current status: Results from 2005 and 2006 show that Arctic terns arrive in poorer energetic condition and are not able to maintain energy stores throughout the breeding season as readily as Common terns. Sampling will continue in 2007. Radar surveys are planned to determine where terns are foraging throughout the breeding season and if foraging ecology can explain differences in their physiology and breeding success.

Impacts
Basic and applied research into the behavioral, ecological, and physiological aspects of habitat use will provide a better understanding about how animals meet their physiological requirements during different life history stages. Plasma hormones, energy metabolites, and immune function, as measures of body condition, are taken throughout different stages of the annual cycle in several species of migrant and resident landbird and seabird species and will provide insight into how environmental factors such as habitat quality and food availability influence breeding and overwintering success. The results from these studies will reveal the physiological basis of different life history strategies and the factors affecting breeding and survival, and underscore the importance of seasonal interactions, i.e. that events during one stage of the annual cycle are not independent of other stages. This approach may help identify where best, during the life cycle of birds, to direct resources and conservation efforts more efficiently.

Publications

• No publications reported this period