scholarly journals Effects of climate on bill morphology within and across Toxostoma thrashers

2021 ◽  
Author(s):  
Charlotte M. Probst ◽  
Joel Ralston ◽  
Ian Bentley
Keyword(s):  
Bill Morphology

scholarly journals A BIOGEOGRAPHIC PATTERN IN SPARROW BILL MORPHOLOGY: PARALLEL ADAPTATION TO TIDAL MARSHES

Evolution ◽  
2005 ◽  
Vol 59 (7) ◽  
pp. 1588-1595 ◽  
Author(s):  
J. Letitia Grenier ◽  
Russell Greenberg
Keyword(s):  
Tidal Marshes ◽  
Biogeographic Pattern ◽  
Bill Morphology

scholarly journals Context-dependent effects of relative temperature extremes on bill morphology in a songbird

2020 ◽  
Vol 7 (4) ◽  
pp. 192203
Author(s):  
Katie LaBarbera ◽  
Kyle J. Marsh ◽  
Kia R. R. Hayes ◽  
Talisin T. Hammond
Keyword(s):  
Extreme Environments ◽  
Negative Relationship ◽  
Environmental Context ◽  
Maximum Temperature ◽  
Relative Temperature ◽  
Generalist Species ◽  
Environmental Extremes ◽  
Bill Morphology ◽  
Thermoregulatory Function ◽  
Cool Climate

Species increasingly face environmental extremes. Morphological responses to changes in average environmental conditions are well documented, but responses to environmental extremes remain poorly understood. We used museum specimens to investigate relationships between a thermoregulatory morphological trait, bird bill surface area (SA) and a measure of short-term relative temperature extremity (RTE), which quantifies the degree that temperature maxima or minima diverge from the 5-year norm. Using a widespread, generalist species, Junco hyemalis , we found that SA exhibited different patterns of association with RTE depending on the overall temperature regime and on precipitation. While thermoregulatory function predicts larger SA at higher RTE, we found this only when the RTE existed in an environmental context that opposed it: atypically cold minimum temperature in a warm climate, or atypically warm maximum temperature in a cool climate. When environmental context amplified the RTE, we found a negative relationship between SA and RTE. We also found that the strength of associations between SA and RTE increased with precipitation. Our results suggest that trait responses to environmental variation may qualitatively differ depending on the overall environmental context, and that environmental change that extremifies already-extreme environments may produce responses that cannot be predicted from observations in less-extreme contexts.

scholarly journals Habitat type and ambient temperature contribute to bill morphology

2014 ◽  
Vol 4 (6) ◽  
pp. 699-705 ◽  
Author(s):  
David Luther ◽  
Russell Greenberg
Keyword(s):  
Ambient Temperature ◽  
Habitat Type ◽  
Bill Morphology

scholarly journals Simulation of Ecological and Evolutionary Interactions of Darwin's Finches—A Multimedia Learning Tool

HortScience ◽  
1997 ◽  
Vol 32 (6) ◽  
pp. 983b-983
Author(s):  
R.D. Quinn
Keyword(s):  
Population Size ◽  
Pilot Project ◽  
Early Summer ◽  
Initial Population ◽  
Introductory Biology ◽  
Web Based ◽  
Darwin's Finches ◽  
Darwin’S Finches ◽  
Large Numbers ◽  
Bill Morphology

Dr. Quinn is one of a team of six biology professors from six different CSU campuses collaborating on this pilot project. EvolvelT is a web-based method for students to learn the fundamentals of natural selection and speciation by simulating natural processes. The simulation will be modeled on the evolution of Darwin's Finches in the Galapagos Islands. Learners will manipulate variables such as initial population size, variability and heritability of bill morphology, and quantity and quality of seeds, and then observe changes with time in population size and bill morphology. The interactive model will allow variables to be changed and simulations to be repeated, producing results that can be graphed and statistically analyzed. The Integrated Technology Strategy (ITS) of the California State University System (CSU) is using the Internet to create new and more flexible learning opportunities. Recently the ITS brought together biologists from several CSU campuses to explore ways to use technology to improve learning in introductory biology laboratories for non-science students. These laboratories were chosen because they affect large numbers of students at all campuses. Development criteria include applicability across the CSU, improvement in learning quality, accessibility to large numbers of students, and measurable success. We selected evolution as a topic for web-based learning because it is a central concept of biology, and it is relatively difficult to teach in conventional introductory biology laboratories. Our development team will work with multimedia design specialists to insure that the web presentation promotes scientifically sound and efficient learning. We are collaborating via e-mail and occasional video conferences and face-to-face meetings. We will work on the actual teaching materials via a web page. The initial prototype will be ready by early summer 1997 and will be tested, modified, and released for beta testing by summer's end.

scholarly journals Environmental correlates and functional consequences of bill divergence in island song sparrows

2021 ◽  
Author(s):  
Maybellene P Gamboa ◽  
Cameron K Ghalambor ◽  
T Scott Sillett ◽  
W Chris Funk ◽  
Ross A Furbush ◽  
...  
Keyword(s):  
Surface Area ◽  
Heat Dissipation ◽  
Song Sparrow ◽  
Maximum Temperature ◽  
Foraging Efficiency ◽  
Channel Islands ◽  
Environmental Selection ◽  
Song Sparrows ◽  
Functional Consequences ◽  
Bill Morphology

Inferring the environmental selection pressures responsible for phenotypic variation is a challenge in adaptation studies as traits often have multiple functions and are shaped by complex selection regimes. We provide experimental evidence that morphology of the multifunctional avian bill is related to climate, not foraging efficiency, in song sparrows (Melospiza melodia) on the California Channel Islands. Our research builds on a study in song sparrow museum specimens that demonstrated a positive correlation between bill surface area and maximum temperature, suggesting a greater demand for dry heat dissipation in hotter, xeric environments. We sampled contemporary sparrow populations across three climatically distinct islands to test the alternate hypotheses that song sparrow bill morphology is either a product of vegetative differences with functional consequences for foraging efficiency or related to maximum temperature and, consequently, important for thermoregulation. Measurements of >500 live individuals indicated a significant, positive relationship between maximum temperature and bill surface area when correcting for body size. In contrast, maximum bite force, seed extraction time, and vegetation on breeding territories (a proxy for food resources) were not significantly associated with bill dimensions. While we cannot exclude the influence of foraging ability and diet on bill morphology, our results are consistent with the hypothesis that variation in song sparrows' need for thermoregulatory capacity across the northern Channel Islands selects for divergence in bill surface area.

Interseasonal and Intersexual Resource Partitioning in Hairy and White-Headed Woodpeckers

The Auk ◽  
1987 ◽  
Vol 104 (2) ◽  
pp. 225-233 ◽  
Author(s):  
Michael L. Morrison ◽  
Kimberly A. With
Keyword(s):  
Resource Use ◽  
Habitat Complexity ◽  
General Trend ◽  
Male And Female ◽  
Winter Foraging ◽  
Bill Morphology ◽  
Morphological Differences ◽  
Differential Ability ◽  
Picoides Villosus ◽  
Negative Relationships

Abstract Foraging behavior in the closely related Hairy (Picoides villosus) and White-headed (P. albolarvatus) woodpeckers was examined in an area of sympatry to evaluate interseasonal and intersexual resource use. Similar foraging heights were observed for each species-sex sample during summer, but significant differences were evident during winter. Male and female White-heads maintained similar relative foraging heights between seasons, whereas male and female Hairies foraged relatively higher during winter. Use of tree species differed significantly for each class between seasons, except for male Hairies. Differences in foraging substrates and tree health also were noted interseasonally. All foraged at similar times of day during summer, but negative relationships occurred between times of foraging during winter; foraging times were significantly different between male Hairies and White-heads. A general trend toward decreased overlap in foraging behaviors during winter was a reflection of concentration of foraging activities on live incense cedar (Calocedrus decurrens), especially by female White-heads. This change apparently was due to the presence of an abundant and accessible prey (incense cedar scale, Xylococculus macrocarpae) on cedar. Behavioral shifts in foraging activities may be related to the differential ability to extract prey as a function of bill morphology; such an idea can be extended to intersexual as well as interseasonal considerations. Thus, segregation of foraging activities in these two woodpecker species may be attributed to morphological differences and habitat complexity rather than to competitive interactions dictated by resource limititions.

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