Each year, billions of dollars are spent on conserving and managing migratory species worldwide. However, decisions on how to allocate funds for conservation are largely based on ad-hoc approaches or simple ranking methods. Our research seeks to integrate demographic and movement data across multiple stages of the annual cycle to develop optimal conservation strategies for migratory species. We use both theoretical- and empirical-based models to explore how various population parameters influence resource allocation decisions.

Selected publications

Sheehy, J, Taylor, CM & Norris, DR. 2011. The importance of stopover habitat for developing effective conservation strategies in migratory animals. In press: J. Ornithology.

10. J.Sheehy, J, Taylor, CM, McCann, KS & Norris, DR. 2010.
    

Optimal conservation of migratory animals: integrating

demographic information across seasons. Conservation

Letters 3: 192-202.

Martin, TM, Chades, I, Arcese, P, Marra, PP, Possingham,

HP & Norris DR. 2007. Optimal conservation of migratory

species. Public Library of Science, One 2(8): e751.

Optimal conservation planning in migratory animals

Understanding the factors that influence population abundance requires knowledge of how events are linked throughout the migratory cycle.  The primary obstacle, thus far, has been the inability to track individuals over large geographic distances, resulting in research that has been limited to isolated stages of the migratory cycle.  Part of the research in our lab has been devoted to developing intrinsic markers such as stable isotopes and trace elements, identifying and understanding the mechanisms behind sources of variance in isotopes and trace elements, and developing statistical tools to assign individuals to specific locations.  The development of such markers has provided us with the ability to develop a species-specific isotopic basemap of North America that includes strontium isotopes, a trace element basemap for a migratory shorebird, and a range-wide connectivity map for a migratory songbird.

Selection publications

Sellick, MJ, Kyser, TK, Wunder, MB, Chipley, D & Norris,

DR. 2009. Geographic variation in strontium and hydrogen

isotopes in avian tissues: implications for tracking migration.

Public Library of Science, One 4(3): e4735.

Wunder, MB & Norris DR. 2008. Improved estimates of

certainty in stable isotope based geographic assignments

for tracking migratory animals. Ecological Applications 18:

549-559.

Betini, GS, Hobson, KA, Wassenaar, L & Norris, DR. 2009.

Stable-hydrogen isotope values in songbird nestlings:

effects of temperature, body size, and diet. Canadian

Journal of Zoology 87: 767-772.

Langin, KM, Reudink, MW, Marra, PP, Norris, DR, Kyser, TK

& Ratcliffe, LM. 2007. Hydrogen isotopic composition of

known-origin migratory birds: implications for geographic

assignment. Oecologia 152: 449-457.

Developing effective tools for tracking migratory animals

Identifying factors that limit the abundance of animals is a critical step towards diagnosing the causes of population decline.  However, for the overwhelming majority of species, we have little information about the historic dynamics of populations.  As a consequence, we face considerable uncertainty about how to discriminate among competing hypotheses of population trend and how to design reliable conservation plans.  Over the last few years, we have developed a comprehensive diet history of Marbled murrelets (Brachyramphus marmoratus) spanning over 150 years. This allows us to examine the causes of variation in population abundance and determine how diet quality is influence by variation in climate.  We are also examining the diet history of a variety of other seabird species that breed in Canada.

Selection publications

Gutowsky, SE, Janssen, MH, Arcese, P, Kyser, TK,

Ethier, D, Wunder, MB, Bertram, DF, McFarlane

Tranquilla, L, Loughheed, C & Norris, DR. 2009. Concurrent

declines in nestling diet quality and reproductive success in

a threatened seabird over 150 years. Endangered Species

Research 9: 247-254.

Norris, DR, Arcese, P, Preikshot, D, Bertram, DF & Kyser,

TK. 2007. Diet reconstruction and historic population

dynamics in a threatened seabird. Journal of Applied

Ecology 44: 875-884.

Reconstructing population dynamics of seabirds

Seasonal interactions and population dynamics of migratory animals

The evolution of migration

Migration is one of the most fascinating behaviours found in nature, but how it evolved in such a wide variety of taxonomic groups and geographic locations has largely remained a mystery.  In collaboration with Caz Taylor and Cort Griswold, one approach our lab has taken for understanding why migration is so common is to develop theoretical models that produce quantitative predictions for the demographic conditions under which migration is expected to evolve from a resident (sedentary) ancestral population.  A second approach we use is to examine the costs and benefits of migratory behaviour in the wild. In collaboration with Alice Boyle and Chris Guglielmo, we test hypotheses related to the proximate and ultimate evolution of migration in a partially migratory population of White-ruffed manakins in Costa Rica.

Selected publications

Boyle, WA, Norris, DR & Guglielmo, CG. 2010. Storms

drive altitudinal migration in a tropical bird. Proceedings of the

Royal Society, London: Biological Sciences 277:2511-2519.

Griswold, CG, Taylor, CM & Norris, DR. 2010. The evolution

of migration in a seasonal environment. Proceedings of the

Royal Society, London: Biological Sciences 277: 2711-2720.

Taylor, CM & Norris, DR. 2007. Predicting conditions for

migration: effects of density-dependence and habitat

quality. Biology Letters 3: 280-283.