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Thomas P. Hahn

D-Index & Metrics

Ecology and Evolution

D-Index
44
Citations
6637
World Ranking
5123
National Ranking
1751

Thomas P. Hahn publication distribution in Ecology and Evolution in 2026

The chart shows the distribution of publications by all Research.com ranked scientists in the field of Ecology and Evolution in 2026. The highlighted bar marks where Thomas P. Hahn sits on this spectrum.

37–41 publications: 2 scientists 42–46 publications: 9 scientists 47–51 publications: 10 scientists 52–56 publications: 31 scientists 57–61 publications: 56 scientists 62–66 publications: 91 scientists 67–71 publications: 92 scientists 72–76 publications: 127 scientists 77–81 publications: 173 scientists 82–86 publications: 236 scientists 87–91 publications: 227 scientists 92–96 publications: 240 scientists 97–101 publications: 333 scientists 102–106 publications: 280 scientists 107–111 publications: 300 scientists 112–116 publications: 285 scientists 117–121 publications: 305 scientists 122–126 publications: 287 scientists 127–131 publications: 278 scientists 132–136 publications: 289 scientists 137–141 publications: 273 scientists 142–146 publications: 262 scientists 147–151 publications: 246 scientists 152–156 publications: 235 scientists 157–161 publications: 205 scientists 162–166 publications: 199 scientists 167–171 publications: 174 scientists 172–176 publications: 164 scientists 177–181 publications: 173 scientists 182–186 publications: 189 scientists 187–191 publications: 170 scientists 192–196 publications: 139 scientists 197–201 publications: 128 scientists 202–206 publications: 117 scientists 207–211 publications: 115 scientists 212–216 publications: 107 scientists 217–221 publications: 124 scientists 222–226 publications: 81 scientists 227–231 publications: 82 scientists 232–236 publications: 85 scientists 237–241 publications: 75 scientists 242–246 publications: 66 scientists 247–251 publications: 81 scientists 252–256 publications: 69 scientists 257–261 publications: 70 scientists 262–266 publications: 55 scientists 267–271 publications: 64 scientists 272–276 publications: 49 scientists 277–281 publications: 48 scientists 282–286 publications: 44 scientists 287–291 publications: 45 scientists 292–296 publications: 36 scientists 297–301 publications: 39 scientists 302–306 publications: 38 scientists 307–311 publications: 30 scientists 312–316 publications: 34 scientists 317–321 publications: 25 scientists 322–326 publications: 22 scientists 327–331 publications: 28 scientists 332–336 publications: 30 scientists 337–341 publications: 22 scientists 342–346 publications: 30 scientists 347–351 publications: 26 scientists 352–356 publications: 22 scientists 357–361 publications: 29 scientists 362–366 publications: 21 scientists 367–371 publications: 12 scientists 372–376 publications: 18 scientists 377–381 publications: 17 scientists 382–386 publications: 13 scientists 387–391 publications: 21 scientists 392–396 publications: 13 scientists 397–401 publications: 10 scientists 402–406 publications: 15 scientists 407–411 publications: 8 scientists 412–416 publications: 9 scientists 417–421 publications: 8 scientists 422–426 publications: 4 scientists 427–431 publications: 10 scientists 432–436 publications: 10 scientists 437–441 publications: 5 scientists 442–446 publications: 4 scientists 447–451 publications: 10 scientists 452–456 publications: 2 scientists 457–461 publications: 4 scientists 462–466 publications: 7 scientists 467–471 publications: 7 scientists 472–476 publications: 6 scientists 477–481 publications: 6 scientists 482–486 publications: 3 scientists 487–491 publications: 3 scientists 492–496 publications: 4 scientists 497–501 publications: 4 scientists 502–506 publications: 8 scientists 507–511 publications: 5 scientists 512–516 publications: 4 scientists 517–521 publications: 5 scientists 522–526 publications: 4 scientists 527–530 publications: 5 scientists 531+ publications: 100 scientists
37 publications 531+

This scientist: 110 publications — 25th percentile

25% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 531 publications or more.

Thomas P. Hahn D-index placement in Ecology and Evolution in 2026

The chart shows the D-index (discipline H-index) distribution of Ecology and Evolution scientists ranked by Research.com in 2026. The highlighted bar marks where Thomas P. Hahn sits on this spectrum.

30 D-Index: 95 scientists 31 D-Index: 123 scientists 32 D-Index: 191 scientists 33 D-Index: 245 scientists 34 D-Index: 252 scientists 35 D-Index: 244 scientists 36 D-Index: 249 scientists 37 D-Index: 244 scientists 38 D-Index: 254 scientists 39 D-Index: 254 scientists 40 D-Index: 280 scientists 41 D-Index: 274 scientists 42 D-Index: 266 scientists 43 D-Index: 233 scientists 44 D-Index: 248 scientists 45 D-Index: 208 scientists 46 D-Index: 201 scientists 47 D-Index: 213 scientists 48 D-Index: 207 scientists 49 D-Index: 172 scientists 50 D-Index: 209 scientists 51 D-Index: 199 scientists 52 D-Index: 153 scientists 53 D-Index: 169 scientists 54 D-Index: 163 scientists 55 D-Index: 148 scientists 56 D-Index: 120 scientists 57 D-Index: 146 scientists 58 D-Index: 137 scientists 59 D-Index: 140 scientists 60 D-Index: 104 scientists 61 D-Index: 119 scientists 62 D-Index: 118 scientists 63 D-Index: 99 scientists 64 D-Index: 77 scientists 65 D-Index: 100 scientists 66 D-Index: 86 scientists 67 D-Index: 83 scientists 68 D-Index: 75 scientists 69 D-Index: 94 scientists 70 D-Index: 57 scientists 71 D-Index: 68 scientists 72 D-Index: 59 scientists 73 D-Index: 63 scientists 74 D-Index: 66 scientists 75 D-Index: 60 scientists 76 D-Index: 42 scientists 77 D-Index: 49 scientists 78 D-Index: 39 scientists 79 D-Index: 37 scientists 80 D-Index: 43 scientists 81 D-Index: 41 scientists 82 D-Index: 45 scientists 83 D-Index: 34 scientists 84 D-Index: 40 scientists 85 D-Index: 35 scientists 86 D-Index: 55 scientists 87 D-Index: 24 scientists 88 D-Index: 24 scientists 89 D-Index: 30 scientists 90 D-Index: 23 scientists 91 D-Index: 25 scientists 92 D-Index: 27 scientists 93 D-Index: 27 scientists 94 D-Index: 13 scientists 95 D-Index: 23 scientists 96 D-Index: 12 scientists 97 D-Index: 14 scientists 98 D-Index: 19 scientists 99 D-Index: 16 scientists 100 D-Index: 14 scientists 101 D-Index: 5 scientists 102 D-Index: 21 scientists 103 D-Index: 16 scientists 104 D-Index: 10 scientists 105 D-Index: 7 scientists 106 D-Index: 7 scientists 107 D-Index: 7 scientists 108 D-Index: 6 scientists 109 D-Index: 9 scientists 110 D-Index: 11 scientists 111 D-Index: 12 scientists 112 D-Index: 9 scientists 113 D-Index: 7 scientists 114 D-Index: 3 scientists 115 D-Index: 8 scientists 116 D-Index: 5 scientists 117 D-Index: 11 scientists 118 D-Index: 4 scientists 119 D-Index: 2 scientists 120 D-Index: 5 scientists 121+ D-Index: 100 scientists
30 D-Index 121+

This scientist: 44 D-Index — 41st percentile

41% of scientists in this discipline score the same or lower.

The last bar groups every scientist with 121 D-Index or more.

Overview

Thomas P. Hahn is affiliated with the University of California, Davis, in the United States. Their research primarily falls within the field of Environmental Science, with a particular focus on subfields such as Ecology, Global and Planetary Change, Ecology, Evolution, Behavior and Systematics, Economics and Econometrics, and Parasitology.

The scientist's work covers key topics including Animal Behavior and Reproduction, Avian Ecology and Behavior, Wildlife Ecology and Conservation, Conservation, Biodiversity, and Resource Management, Bird Parasitology and Diseases, Forest Management and Policy, as well as Economic and Environmental Valuation.

Selected recent publications by Thomas P. Hahn include the following:

  • "Diverse values of nature for sustainability," 2023, Nature
  • "Evolution of the polycrisis: Anthropocene traps that challenge global sustainability," 2023, Philosophical Transactions of the Royal Society B Biological Sciences
  • "Specified resilience value of alternative forest management adaptations to storms," 2021, Scandinavian Journal of Forest Research
  • "Mind the Compliance Gap: How Insights from International Human Rights Mechanisms Can Help to Implement the Convention on Biological Diversity," 2021, Transnational Environmental Law
  • "Incorporating diverse values of nature in decision-making-theory and practice," 2024, Philosophical Transactions of the Royal Society B Biological Sciences

Thomas P. Hahn frequently publishes research in venues such as tanz, Philosophical Transactions of the Royal Society B Biological Sciences, Nature Communications, General and Comparative Endocrinology, and PLoS ONE.

Frequent collaborators in their research include Elizabeth M. Schultz, John C. Wingfield, Mikael Karlsson, Jamie M. Cornelius, and Johannes Morfeldt. These coauthors often appear jointly on multiple scientific works with Hahn.

Best Publications

  • In search of relationships between the acute adrenocortical response and fitness

    Creagh W. Breuner;Stephen H. Patterson;Thomas P. Hahn

  • Testosterone and territorial behaviour in sedentary and migratory sparrows

    John C. Wingfield;Thomas P. Hahn

  • Environmental predictability and control of gonadal cycles in birds

    John C. Wingfield;Thomas P. Hahn;Rachel Levin;Pulmu Honey

  • Development of stress reactivity in white-crowned sparrow nestlings: total corticosterone response increases with age, while free corticosterone response remains low.

    Haruka Wada;Thomas P. Hahn;Creagh W. Breuner

  • Integrating stress physiology, environmental change, and behavior in free-living sparrows

    Creagh W Breuner;Thomas P Hahn

  • Differential mechanisms for regulation of the stress response across latitudinal gradients

    C. W. Breuner;Miles Orchinik;T. P. Hahn;S. L. Meddle

  • Effects of temperature on photoperiodically induced reproductive development, circulating plasma luteinizing hormone and thyroid hormones, body mass, fat deposition and molt in mountain white-crowned sparrows, Zonotrichia leucophrys oriantha.

    John C. Wingfield;Thomas P. Hahn;Donna L. Maney;Stephan J. Schoech

  • Integration of photoperiodic and food cues to time changes in reproductive physiology by an opportunistic breeder, the red crossbill, Loxia curvirostra (Aves: Carduelinae)

    Thomas P. Hahn;Thomas P. Hahn

  • Temporal Flexibility in Avian Reproduction

    Thomas P. Hahn;Timothy Boswell;John C. Wingfield;Gregory F. Ball

  • REPRODUCTIVE SEASONALITY IN AN OPPORTUNISTIC BREEDER, THE RED CROSSBILL, LOXIA CURVIROSTRA

    Thomas P. Hahn

  • Effects of Day Length and Temperature on Gonadal Development, Body Mass, and Fat Depots in White-Crowned Sparrows,Zonotrichia leucophrys pugetensis ☆

    John C. Wingfield;John C. Wingfield;Thomas P. Hahn;Thomas P. Hahn;Masaru Wada;Masaru Wada;Stephan J. Schoech;Stephan J. Schoech

  • Interrelationship of Day Length and Temperature on the Control of Gonadal Development, Body Mass, and Fat Score in White-Crowned Sparrows,Zonotrichia leucophrys gambelii

    John C. Wingfield;Thomas P. Hahn;Masaru Wada;Lee B. Astheimer

  • Endocrine influences on parental care during a short breeding season : testosterone and male parental care in Lapland longspurs (Calcarius lapponicus)

    Kathleen E. Hunt;Thomas P. Hahn;John C. Wingfield

  • Adaptive specialization, conditional plasticity and phylogenetic history in the reproductive cue response systems of birds

    Thomas P Hahn;Scott A MacDougall-Shackleton

  • Testosterone implants increase song but not aggression in male Lapland longspurs

    Kathleen E Hunt;Thomas P Hahn;John C Wingfield

  • Immediate early gene response to hearing song correlates with receptive behavior and depends on dialect in a female songbird.

    D. L. Maney;D. L. Maney;E. A. MacDougall-Shackleton;S. A. MacDougall-Shackleton;G. F. Ball

  • Adjustments of the prebasic molt schedule in birds

    T. P. Hahn;J. Swingle;J. C. Wingfield;M. Ramenofsky

  • Long-Term Persistence of Song Dialects in the Mountain White-Crowned Sparrow

    Heidi Harbison;Douglas A. Nelson;Thomas P. Hahn

  • Changes in brain GnRH associated with photorefractoriness in house sparrows (Passer domesticus).

    Thomas P. Hahn;Gregory F. Ball

  • Territoriality and testosterone in an equatorial population of rufous-collared sparrows, Zonotrichia capensis

    Ignacio T Moore;Haruka Wada;Nicole Perfito;D.Shallin Busch

  • Recent advances in behavioral neuroendocrinology: Insights from studies on birds

    James L. Goodson;Colin J. Saldanha;Thomas P. Hahn;Kiran K. Soma

  • Natural selection and glucocorticoid physiology

    S. H. Patterson;T. P. Hahn;J. M. Cornelius;C. W. Breuner

  • House finches (Carpodacus mexicanus) balance investment in behavioural and immunological defences against pathogens

    Maxine Zylberberg;Kirk C. Klasing;Thomas P. Hahn

Frequent Co-Authors

Scott A. MacDougall-Shackleton
Scott A. MacDougall-Shackleton University of Western Ontario
John C. Wingfield
John C. Wingfield University of California, Davis
Gregory F. Ball
Gregory F. Ball University of Maryland, College Park
Creagh W. Breuner
Creagh W. Breuner University of Montana
Kirk C. Klasing
Kirk C. Klasing University of California, Davis
Martin L. Morton
Martin L. Morton Occidental College
George E. Bentley
George E. Bentley University of California, Berkeley
Elizabeth P. Derryberry
Elizabeth P. Derryberry University of Tennessee at Knoxville
Ellen D. Ketterson
Ellen D. Ketterson Indiana University
Andrew N. Iwaniuk
Andrew N. Iwaniuk University of Lethbridge

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Related Online Degrees & Career Pathways

Exploring ecology and evolution can open doors to diverse and rewarding career paths. Many students find that related subjects, such as human services or even mathematics, provide a strong foundation for jobs in conservation, research, and public policy. If you’re interested in a flexible, people-focused education, the human services degree online offers practical skills for community outreach and environmental advocacy roles.

Those considering a career switch may also look to options outside the traditional science track. For example, teachers seeking new opportunities can explore a career change for teachers higher pay by moving into specialized fields such as speech-language pathology, which can complement educational and environmental programming.

Innovative intersections also exist between ecology and design, making the best online architecture degree programs appealing for those interested in green buildings or sustainable landscapes. Analytical skills are highly valued in this field, and the growth in online math degree programs can empower you with the quantitative expertise needed for data-driven research in ecology or evolutionary biology.

Best Scientists Citing Thomas P. Hahn

John C. Wingfield

John C. Wingfield

University of California, Davis

Publications: 167

Gregory F. Ball

Gregory F. Ball

University of Maryland, College Park

Publications: 58

Michaela Hau

Michaela Hau

University of Konstanz

Publications: 51

George E. Bentley

George E. Bentley

University of California, Berkeley

Publications: 51

Ignacio T. Moore

Ignacio T. Moore

Virginia Tech

Publications: 49

Ellen D. Ketterson

Ellen D. Ketterson

Indiana University

Publications: 40

Wolfgang Goymann

Wolfgang Goymann

Max Planck Society

Publications: 39

Creagh W. Breuner

Creagh W. Breuner

University of Montana

Publications: 38

Frédéric Angelier

Frédéric Angelier

Centre national de la recherche scientifique, CNRS

Publications: 38

Scott A. MacDougall-Shackleton

Scott A. MacDougall-Shackleton

University of Western Ontario

Publications: 33

Olivier Chastel

Olivier Chastel

Centre national de la recherche scientifique, CNRS

Publications: 33

Tony D. Williams

Tony D. Williams

Simon Fraser University

Publications: 31

Lynn B. Martin

Lynn B. Martin

University of South Florida

Publications: 26

Jacques Balthazart

Jacques Balthazart

University of Liège

Publications: 26

Oliver P. Love

Oliver P. Love

University of Windsor

Publications: 25

Barbara Helm

Barbara Helm

University of Glasgow

Publications: 24

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