Former Editor-in-Chief of Avian Conservation and Ecology, Dr. Keith Alan Hobson (FRSC), regretfully passed away on 2 October 2024, at the age of 70 following a brief battle with cancer. Over his scientific career, Keith established himself as a world-renowned scientist across several fields. Having authored or co-authored more than 650 peer-reviewed manuscripts, edited 2 books, and written 16 book chapters, Keith’s enormous productivity, creativity, extraordinary network of collaborators, and his tireless efforts in mentoring a new generation of scientists helped bring international attention to Canadian science and make Avian Conservation and Ecology internationally influential in ornithology.

Keith’s career in ornithology was inspired by a childhood love of nature and a fascination for birds, in particular. Born in Harrow, England, on 10 July 1954, Keith and his family immigrated to Vancouver, BC, Canada in 1966. His early intellectual interests in science inspired him to pursue a Bachelor of Science in Physics from Simon Fraser University (SFU) in British Columbia, Canada. After completing his BSc in 1977, he spent the following seven years working in the SFU Archaeology Department’s radiocarbon dating lab. This initial “distraction” could not keep Keith from applying his keen mind to ornithology for long, but did serve to pique his interest in possible applications of stable isotope methods to ecological questions.

When Keith finally pursued his love of ornithology, he hoped to study seabirds on the Pacific Coast with Dr. Spencer Sealy (University of Manitoba) as his supervisor. Prior to beginning graduate studies, Keith indulged his fascination with cormorants by examining colony site and roost site selection by Pelagic Cormorants (Urile pelagicus) in Barkley Sound, British Columbia (Carter et al. 1984, Hobson and Sealy 1986), as well as crèching behavior of Brandt’s Cormorant (Urile penicillatus) chicks (Carter and Hobson 1988) with that work done prior to enrolling in graduate studies. Keith would later return to his interest in cormorants throughout his career (Hobson 2009, Ofukany et al 2015). However, circumstances compelled Keith to turn his attention to the protection of genetic parentage and cowbird parasitism in Yellow Warblers (Setophaga petechia) and he completed his M.Sc. degree (Hobson 1988). Keith was not content to only take on his primary M.Sc. research, however, and he simultaneously worked on several side research projects, including work on the contributions of marine proteins to the diet of the Northern Saw-whet Owl (Aegolius acadicus; Hobson and Sealy 1991), ground foraging behavior of swallows (Hobson and Sealy 1987), and female song in Yellow Warbler (Hobson and Sealy 1990), in addition to publishing several papers in archaeological science stemming from his early career (e.g., Collier and Hobson 1987).

Keith’s M.Sc. field work was conducted at the University of Manitoba Delta Marsh Field Station (Hobson et al. 2012). Time there led him to realize the value of the Lake Manitoba shores as a migratory stopover site. As a result, Dr. Hobson became a Founding Member and Executive Board Member of the Delta Marsh Bird Observatory, which is part of the Canadian Migration Monitoring Network (CMMN). This early linkage to CMMN was the beginning of a career-long collaboration with the CMMN and Birds Canada, the CMMN’s umbrella organization. Keith’s work with Birds Canada has included serving as Chair of the Science Advisory Board (2006–2012), and work to determine the migratory origins of birds passing through CMMN stations (Dunn et al. 2006, Hobson et al. 2015).

After completing his M.Sc., Keith returned to studying seabirds as was his original interest by completing his Ph.D. with Dr. Malcolm Ramsay at the University of Saskatchewan. Based on the knowledge Keith gained during his time working in archaeology, he thought that stable isotopes should allow him to trace the flow of nutrients from primary producers through to top carnivores and his Ph.D. demonstrated that the high arctic ecosystem was a great testing ground for this approach (Hobson 1991).

After completing his Ph.D., Keith continued applying stable isotope methods to examine arctic ecosystem trophic ecology in a postdoctoral position with the Freshwater Institute of Fisheries and Oceans Canada. It was not long, however, before Keith’s talents would lead to him quickly landing a permanent position. Indeed, in 1992, Keith was hired as a Senior Research Scientist with Environment and Climate Change Canada (ECCC), a position he held until his retirement in September of 2024. In the first years of his career with ECCC, Dr. Hobson quickly prioritized several lines of scientific inquiry. On one front, he continued to develop the application of isotopic tools for ecological studies. The other major focus of Keith’s early ECCC research focused on the ecology and conservation of forest birds, including how anthropogenic disturbances influence forest bird communities.

Keith built upon his trophic ecology work by completing laboratory studies to address key assumptions in application of isotopes to dietary studies (Hobson and Clark 1992a, b, Gloutney and Hobson 1998). Combined with his earlier work demonstrating that nutrients could be traced through food webs (Hobson and Welch 1992, Hobson et al. 1994), his studies became foundational to how isotopes were applied in food web ecology. It was also at this time that Keith began long-term collaboration with Dr. Len Wassenaar, who at the time was a Research Scientist with ECCC specializing in stable isotope hydrology. Together, Len and Keith realized that spatially predictable patterns of hydrogen isotope ratios in rainfall known from data collected by the International Atomic Energy Agency should also be reflected in the tissues of animals. After obtaining known-origin feathers from across much of North America, they demonstrated that the technique could be used for tracing molt origins of migratory birds (Hobson and Wassenaar 1996). Len and Keith followed up on this work with a combination of captive rearing of Monarch butterflies (Danaus plexippus) on known isotope ratio waters across the breeding range in addition to sampling Monarch wings in their wintering colonies (Wassenaar and Hobson 1998). Not only did this provide further evidence of the value of the method, but it also introduced Keith to his soulmate B. Xiomara Mora Alvarez whom he met while they were both working in Monarch colonies in Mexico. In addition to those breakthroughs, Keith’s collaboration with Peter Marra’s demonstrating that arrival dates of American Redstarts (Setophaga ruticilla) on the breeding grounds was influenced by wintering ground habitat quality (Marra et al. 1998) helped to spur emphasis on migratory connectivity and cross-seasonal effects in ornithology in the subsequent decades.

It was not long before Keith and his colleagues demonstrated how isotopic methods could trace the flow and biomagnification of contaminants in the environment (Atwell et al. 1998, Fiske et al. 2001). These approaches have allowed Keith and colleagues to tackle pressing questions such as whether increases in contaminants have contributed to declines in the endangered Ivory Gull (Pagophila eburnea; Bond et al. 2015). Importantly, these methods allow for examination of whether changes in contaminant concentrations derive from shifts in diet versus increases in the background contaminant levels (Bond et al. 2015, Choy et al. 2022).

Although Keith’s innovative isotope ecology work has received much of the spotlight, he also had a reputation for his applied conservation work. When he began his career with ECCC, Keith recognized that increasing anthropogenic disturbance in the boreal forest required directed research. He quickly began addressing the impact of forest change and fragmentation on nest predation rates (Bayne and Hobson 1997) and avian community composition (Hobson and Bayne 2000), how leaving live patches of residual trees within forest harvests influenced community change (Hobson and Schieck 1999, Schieck and Hobson 2000), and avian responses to various experimental forestry techniques (Van Wilgenburg and Hobson 2008, Kardynal et al. 2011). An important aspect of Keith’s focus with this applied research was to inform policy, and much of this work resulted in either the creation or support for specific forestry guidelines to mitigate impacts of forest harvesting on the bird community.

Keith has long said that conservation of migratory birds is futile if threats across the annual cycle are not also considered (Faaborg et al. 2010). True to this conviction, Keith recently focused on working with Latin American scientists to address conservation of Neotropical migrant and endemic birds by supporting and mentoring local scientists. The work Keith supported in Latin America had significant conservation implications, with key examples including examining the value of shade coffee plantations for migratory birds (González et al. 2020, 2021), catchment origins of birds migrating though a geographic bottleneck (Cardenas-Ortiz et al. 2020), the role of overwintering sites in shaping migration strategies (Bayly et al. 2020), risk of avian influenza being introduced into Cuba (Rodríguez-Ochoa et al. 2024), shifts in migratory origins (Gómez et al. 2021), and factors influencing the occupancy and abundance of Blackpoll Warbler (Setophaga striata) in Colombia (Morales-Rojo et al. 2024). Keith was also instrumental in the recent expansion of the Motus wildlife tracking network (https://motus.org/) in Colombia (2017) and Cuba (2024). As a result of these collaborations and mentoring Latin American students, Keith’s efforts made a significant impact on strengthening Neotropical ornithology and the capacity of Latin American ornithological science.

Although most of Keith’s career was spent as a senior Research Scientist with ECCC, he very quickly developed associations with numerous universities where he had a profound role in teaching and mentoring young scientists. Keith was an adjunct professor at the University of Saskatchewan (1992–2024), Research Scientist in residence and adjunct professor at Western University (2015–2017) where he was later appointed as a Distinguished Professor (2018–2024), and an adjunct professor at Dalhousie University (2017–2024). In these roles, Keith supervised 13 Ph.D. students, 29 M.Sc. students, and was an external examiner for at least 9 other graduate students.

Beyond the influence Keith’s publications have had, Keith also made enormous contributions to Canadian and international ornithology through peer-review and editing. Dr. Hobson was a firm believer in supporting the peer-review process and provided peer-review for over 48 scientific journals and granting agencies. Keith served as Editor of Waterbirds (2005–2008) and was on the editorial boards of Auk, Condor, Écoscience, Journal of Ornithology, and Marine Ecology Progress Series. More recently, Dr. Hobson became a topic editor (New frontiers in the application of stable isotopes to ecological and ecophysiological research) for Frontiers in Ecology and Evolution. In addition, Keith’s tenure as Editor-in-Chief of Avian Conservation and Ecology (2012–2020) saw an era of unprecedented growth in the number of contributions, readership, and citations. Under Keith’s guidance, Avian Conservation and Ecology went from 12 articles published and 33 citations per year to 45 articles published and 697 citations in 2020. The international reach of Avian Conservation and Ecology has since blossomed, with recent contributions not only from Canada and the USA, but also Australia, China, Mexico, Taiwan, the Philippines, Korea, Bangladesh, and the South Pacific, to name a few. Keith also used these positions to further mentor young scientists by emphasizing peer-review opportunities for graduate students and invited several young scientists to join the editorial boards of the journals he edited.

Keith received numerous awards in recognition of his significant contributions and innovation. Keith was awarded the AOS’s Elliot Coues award (2007) for outstanding contributions to Ornithology, the Loye and Alden Miller Research Award (2010), and the Katma Award (2011) for the paper “Migratory double breeding in Neotropical migrant birds” (with Drs. Sievert and Vanya Rohwer; Rohwer et al. 2009). In 2011, Keith won the Society of Canadian Ornithologist’s Doris Huestis Speirs Award. Keith also received awards from ECCC including the Geoff Howell Citation of Excellence for Innovation (2005 and 2018), and was made a Fellow of the American Ornithologists Union (2004), the Royal Society of Canada (2013), and the International Ornithological Union (2018), as well as a corresponding Member of the German Ornithologist’s Society (2011).

Keith displayed his extraordinary dedication until his final days, still providing reviews and comments on manuscripts to young graduate students only days before his demise. He was always quick to provide his opinion and advice and has both mentored and inspired a new generation of young scientists in Canada and abroad. In addition to being known for his dedication to science and conservation, he was well known for his quick wit, charm, and ability to reduce a problem to the essential facts. Keith will be missed by his friends, colleagues, mentees, and family, but his legacy as a scientist and mentor will leave a mark on Canadian ornithology for decades to come.

LITERATURE CITED

Atwell, L., K. A. Hobson, and H. E. Welch. 1998. Biomagnification and bioaccumulation of mercury in an Arctic marine food web: insights from stable-nitrogen isotope analysis. Canadian Journal of Fisheries and Aquatic Science 55:1114-1121. https://doi.org/10.1139/f98-001

Bayly, N. J., D. R. Norris, P. D. Taylor, K. A. Hobson, and A. Morales-Rozo. 2020. There’s no place like home: tropical over-winter sites may have a fundamental role in shaping migratory strategies. Animal Behaviour 162:95-104. https://doi.org/10.1016/j.anbehav.2020.02.003

Bayne, E. M., and K. A. Hobson. 1997. Comparing the effects of landscape fragmentation by forestry and agriculture on predation of artificial nests. Conservation Biology 11:1418-1429. https://doi.org/10.1046/j.1523-1739.1997.96135.x

Bond, A., K. A. Hobson, and B. A. Branfireun. 2015. Rapidly increasing methyl mercury in endangered ivory gull (Pagophila eburnea) feathers over a 130 year record. Proceeding of the Royal Society London, series B 282:20150032. https://doi.org/10.1098/rspb.2015.0032

Cardenas-Ortiz, L., N. J. Bayly, K. J. Kardynal, and K. A. Hobson. 2020. Defining catchment origins of a geographical bottleneck: implications of population mixing and phenological overlap for the conservation of Neotropical migratory birds. Condor 122:duaa004. https://doi.org/10.1093/condor/duaa004

Carter, H. R., and K. A. Hobson. 1988. Creching behaviour of Brandt’s Cormorant chicks. Condor 90:395-400. https://doi.org/10.2307/1368568

Carter, H. R., K. A. Hobson, and S. G. Sealy. 1984. Colony site selection by Pelagic Cormorants (Phalacrocorax pelagicus) in Barkley Sound, British Columbia. Colonial Waterbirds 7:25-34. https://doi.org/10.2307/1521079

Choy, E. S., L. K. Blight, J. Elliott, K. A. Hobson, M. Zanuttig, and K. H. Elliott. 2022. Stable mercury trends support a long-term diet shift away from marine foraging in Salish Sea Glaucous-Winged Gulls over the last century. Environmental Science and Technology 56:12097-12105. https://doi.org/10.1021/acs.est.1c03760

Collier, S., and K. A. Hobson. 1987. The importance of marine protein in the diet of coastal Australian Aborigines. Current Anthropology 28:559-564. https://doi.org/10.1086/203560

Dunn, E. H., K. A. Hobson, L. I. Wassenaar, D. Hussell, and M. L. Allen. 2006. Identification of summer origins of songbirds migrating through southern Canada in autumn. Avian Conservation and Ecology 1(2):4. https://doi.org/10.5751/ACE-00048-010204

Faaborg, J., R. T. Holmes, A. D. Anders , K. L. Bildstein , K. M. Dugger , S. A. Gauthreaux, Jr. , P. Heglund , K. A. Hobson , A. E. Jahn , D. H. Johnson, S. C. Latta , D. J. Levey , P. P. Marra, C. L. Merkord, E. Nol, S. I. Rothstein, T. W. Sherry, T. S. Sillett, F. R. Thompson III, and N. Warnock. 2010. Conserving migratory landbirds in the New World: Do we know enough? Ecological Applications 20:398-418. https://doi.org/10.1890/09-0397.1

Fisk, A. T., K. A. Hobson, and R. J. Norstrom. 2001. Influence of chemical and biological factors on trophic transfer of persistent organic pollutants in the Northwater Polynya marine food web. Environmental Science & Technology 35:732-738. https://doi.org/10.1021/es001459w

Gloutney, M. L., and K. A. Hobson. 1998. Field preservation techniques for the analysis of stable-carbon and nitrogen isotope ratios in eggs. Journal of Field Ornithology 69:223-227.

Gómez, C., K. A. Hobson, N. J. Bayly, K. V. Rosenberg, A. Morales-Rozo, P. Cardozo, and C. D. Cadena. 2021. Migratory connectivity then and now: a northward shift in breeding origins of a long-distance migratory bird wintering in the tropics. Proceedings of the Royal Society B 288(1948):20210188. https://doi.org/10.1098/rspb.2021.0188

González, A. M., N. J. Bayly, S. Wilson, and K. A. Hobson. 2021. Shade coffee or native forest? Indicators of winter habitat quality for a long-distance migratory bird in the Colombia Andes. Ecological Indicators 131:108115. https://doi.org/10.1016/j.ecolind.2021.108115

González, A. M., S. Wilson, N. J. Bayly, and K. A. Hobson. 2020. Contrasting the suitability of shade coffee agriculture and native forest as overwinter habitat for Canada Warbler (Cardellina canadensis) in the Colombian Andes. Condor 122:duaa011. https://doi.org/10.1093/condor/duaa011

Hobson, K. A. 1988. Protection of genetic parentage in the Yellow Warbler (Dendroica petechia). Thesis. University of Manitoba, Winnipeg, Manitoba, Canada.

Hobson, K. A. 1991. Use of stable carbon and nitrogen isotope analysis in seabird dietary studies. Dissertation. University of Saskatchewan, Saskatoon, Saskatchewan, Canada.

Hobson, K. A. 2009. Trophic interactions between cormorants and fisheries: towards a more quantitative approach using stable isotopes. Waterbirds 32:481-490. https://doi.org/10.1675/063.032.0401

Hobson, K. A., and E. M. Bayne. 2000. Effects of forest fragmentation by agriculture on avian communities in the southern boreal mixedwoods of western Canada. Wilson Bulletin 112:373-387. https://doi.org/10.1676/0043-5643(2000)112[0373:EOFFBA]2.0.CO;2

Hobson, K. A., and R. W. Clark. 1992a. Assessing avian diets using stable isotopes. I: turnover of ¹³C in tissues. Condor 94:181-188. https://doi.org/10.2307/1368807

Hobson, K. A., and R. W. Clark. 1992b. Assessing avian diets using stable isotopes. II: factors influencing diet-tissue fractionation. Condor 94:189-197. https://doi.org/10.2307/1368808

Hobson, K. A., D. R. Norris, G. Goldsborough, and S. G. Sealy. 2012. Requiem for a field station: the loss of a Canadian ornithological treasure. Avian Conservation and Ecology 7(2):7. https://doi.org/10.5751/ACE-00553-070207

Hobson, K. A., J. F. Piatt, and J. Pitocchelli. 1994. Using stable isotopes to determine seabird trophic relationships. Journal of Animal Ecology 63:786-798. https://doi.org/10.2307/5256

Hobson, K. A., and J. Schieck.1999. Changes in bird communities in boreal mixedwood forest: harvest and wildfire effects over 30 years. Ecological Applications 9:849-863. https://doi.org/10.1890/1051-0761(1999)009[0849:CIBCIB]2.0.CO;2

Hobson, K. A., and S. G. Sealy. 1986. Use of diurnal roosting sites by Pelagic Cormorants in Barkley Sound, British Columbia. Murrelet 67:65-74. https://doi.org/10.2307/3536459

Hobson, K. A., and S. G. Sealy. 1987. Foraging, scavenging and other behavior of swallows on the ground. Wilson Bulletin 99:111-116.

Hobson, K. A., and S.G. Sealy. 1990. Female song in the Yellow Warbler. Condor 92:259-261. https://doi.org/10.2307/1368416

Hobson, K. A., and S. G. Sealy. 1991. Marine protein contributions to the diets of Northern Saw-whet Owls on the Queen Charlotte Islands, British Columbia: a stable isotope approach. Auk 108:437-440.

Hobson, K. A., S. L. Van Wilgenburg, E. H. Dunn, D. J. T. Hussell, P. D. Taylor, and D. M. Collister. 2015. Predicting origins of passerines migrating through Canadian migration monitoring stations using stable-hydrogen isotope analyses of feathers: a new tool for bird conservation. Avian Conservation and Ecology 10(1):3. https://doi.org/10.5751/ACE-00719-100103

Hobson, K. A., and L. I. Wassenaar. 1996. Linking breeding and wintering grounds of Neotropical migrant songbirds using stable hydrogen isotopic analysis of feathers. Oecologia 109:142-148. https://doi.org/10.1007/s004420050068

Hobson, K. A., and H. E. Welch. 1992. Determination of trophic relationships within a high Arctic marine food web using δ¹³C and δ¹⁵N analysis. Marine Ecology Progress Series 84:9-18. https://doi.org/10.3354/meps084009

Kardynal, K. J., J. L. Morissette, S. L Van Wilgenburg, E. M. Bayne, and K. A. Hobson. 2011. Avian responses to experimental harvest in southern boreal mixedwood shoreline forests: implications for riparian buffer management. Canadian Journal of Forest Research 41:2375-2388. https://doi.org/10.1139/x11-145

Marra, P. P., K. A. Hobson, and R. T. Holmes. 1998. Linking winter and summer events in a migratory bird using stable carbon isotopes. Science 282:1884-1886. https://doi.org/10.1126/science.282.5395.1884

Morales-Rojo, A., N. J. Bayly, P. D. Taylor, K. A. Hobson, G. J. Colorado, and J. P. Gómez. 2024. A multiscale analysis of factors influencing Setophaga striata (Blackpoll Warbler) occupancy and abundance during the nonbreeding season in eastern Colombia. Ornithological Applications duae051. https://doi.org/10.1093/ornithapp/duae051

Ofukany, F. A., K. A. Hobson, L. I. Wassenaar, and A. L. Bond. 2015. Prey consumption and trace element concentrations in Double-crested Cormorants (Phalacrocorax auritus) from Lake Winnipeg, Canada. Journal of Great Lakes Research 41:643-651. https://doi.org/10.1016/j.jglr.2015.03.008

Rodríguez-Ochoa, A., J. W. Kusack, L. Mugica, M. Acosta Cruz, P. Alfonso, B. Delgado Hernandez, Y. Abreu, E. García, and K. A. Hobson. 2024. Migratory connectivity of Blue-winged Teal: risk implications for avian influenza virus introduction to Cuba. Frontiers in Bird Science 3:1401625 https://doi.org/10.3389/fbirs.2024.1401625

Rohwer, S., K. A. Hobson, and V. G. Rohwer. 2009. Migratory double breeding in Neotropical migrant birds. Proceedings of the National Academy of Sciences 106:19050-19055 https://doi.org/10.1073/pnas.0908121106

Schieck, J., and K. A. Hobson. 2000. Bird communities associated with live residual tree patches within cut blocks and burned habitat in mixedwood boreal forests. Canadian Journal of Forest Research 30:1281-1295. https://doi.org/10.1139/x00-061

Van Wilgenburg, S. L., and K. A. Hobson. 2008. Landscape-scale disturbance and boreal forest birds: Can large single-pass harvest approximate fires? Forest Ecology and Management 256:136-146. https://doi.org/10.1016/j.foreco.2008.04.017

Wassenaar, L. I., and K. A. Hobson. 1998. Natal origins of migratory Monarch Butterflies at wintering colonies in Mexico: new isotopic evidence. Proceedings of the National Academy of Sciences 95:15436-15439. https://doi.org/10.1073/pnas.95.26.15436