Douglas Eifler

Dr. Douglas Eifler


Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 August 2023 in Ecology and Evolution
Verified
Journal Article
Open access
EMElizabeth McAlpine‐Bellis
Elizabeth McAlpine‐Bellis
KUKaera Utsumi
Kaera Utsumi
KDKelly M. Diamond
Kelly M. Diamond
JKJanine Klein
Janine Klein
SGSophia Gilbert‐Smith
Sophia Gilbert‐Smith
DEDouglas A Eifler
Douglas A Eifler
Movement is an important characteristic of an animal's ecology, reflecting the perception of and response to environmental conditions. To effectively search for food, movement patterns likely depend on habitat characteristics and the sensory systems used to find prey. We examined movements associated with foraging for two sympatric species of lizards inhabiting the Great Basin Desert of southeastern Oregon. The two species have largely overlapping diets but find prey via different sensory cues, which link to their differing foraging strategies—the long‐nosed leopard lizard, Gambelia wislizenii, is a visually‐oriented predator, while the western whiptail, Aspidoscelis tigris, relies more heavily on chemosensory cues to find prey. Using detailed focal observations, we characterized the habitat use and movement paths of each species. We placed markers at the location of focal animals every minute for the duration of each 30‐min observation. Afterward, we recorded whether each location was in the open or in vegetation, as well as the movement metrics of step length, path length, net displacement, straightness index, and turn angle, and then made statistical comparisons between the two species. The visual forager spent more time in open areas, moved less frequently over shorter distances, and differed in patterns of plant use compared to the chemosensory forager. Path characteristics of step length and turn angle differed between species. The visual predator moved in a way that was consistent with the notion that they require a clear visual path to stalk prey whereas the movement of the chemosensory predator increased their chances of detecting prey by venturing further into vegetation. Sympatric species can partition limited resources through differences in search behavior and habitat use.

22 July 2016 in Journal of Ethology
Verified
Journal Article
Closed access
PDF file
DEDouglas A Eifler
Douglas A Eifler
MEMaria Eifler
Maria Eifler
KMKeoleboge Malela
Keoleboge Malela
JCJackie Childers
Jackie Childers

17 February 2020 in Western North American Naturalist
Verified
Journal Article
Closed access
PDF file
KUKaera Utsumi
Kaera Utsumi
CKCarina Kusaka
Carina Kusaka
RPRachael Pedersen
Rachael Pedersen
CSCatherine Staley
Catherine Staley
LDLisa Dunlap
Lisa Dunlap
DEDouglas A Eifler
Douglas A Eifler
We compared the movement patterns of foraging Colorado Checkered Whiptails (Aspidoscelis neotesselata) in 2 different habitat types: shrub-grassland and pinyon pine–juniper woodland. We characterized movement by (1) segmenting movement paths into step lengths and turn angles and (2) determining first-passage times (FPTs). Lizards differed in their pattern of movement in the 2 habitats. FPTs were shorter in the pinyon pine–juniper woodland habitat and were positively correlated with ground cover. Lizards also moved more frequently, had longer step lengths, and traveled greater total distances in the pinyon pine–juniper woodland. There were no habitat differences in turn angles, net displacement, or movement path straightness. Habitat-based differences in movement might reflect differences in prey availability and predation risk.

25 December 2023 in African Journal of Ecology
Verified
Journal Article
Closed access
DEDouglas A Eifler
Douglas A Eifler
MEMaria A Eifler
Maria A Eifler
MOMakenna Orton
Makenna Orton
KUKaera Utsumi
Kaera Utsumi
MJMohsen Jarray
Mohsen Jarray
MCMohsen CHAMMEM
Mohsen CHAMMEM

1 January 2016 in Amphibia-Reptilia
Verified
Journal Article
Closed access
PDF file
GGGrace Garrison
Grace Garrison
MPMia Phillips
Mia Phillips
MEMaria A Eifler
Maria A Eifler
DEDouglas A Eifler
Douglas A Eifler
Ameiva corax is restricted to a small island (<2 ha), off the coast Anguilla. We present information on intraspecific variation in its diet, based on observations of 190 marked individuals. Larger individual were more likely to attempt to enter active seabird nests and only large males were observed to successfully enter a nest and break open an egg. Flower eating was commonly observed and its occurrence was not related to lizard size or sex. More than half the population was observed visiting areas where fisherman mixed their bait, a foraging strategy also unrelated to lizard size or sex. Ameiva corax is known to socially feed at large food items such as seabird eggs. The individuals that can initially access these food items may occupy key roles in the social network.

1 December 2021 in Western North American Naturalist
Verified
Journal Article
Closed access
PDF file
CKCarina Kusaka
Carina Kusaka
KUKaera Utsumi
Kaera Utsumi
CSCatherine Staley
Catherine Staley
RPRachael Pedersen
Rachael Pedersen
JVJulia Valdivia
Julia Valdivia
DEDouglas A Eifler
Douglas A Eifler
We compared movement and space use patterns of foraging adult and juvenile Colorado checkered whiptails (Aspidoscelis neotesselatus) in pinyon pine–juniper woodland. Through focal observations, we characterized (1) movement paths as a series of step lengths and turn angles at 30-s intervals, and (2) habitat use reflected by the proportion of time spent in different vegetation types and in the open. Adults and juveniles differed in both movement and habitat use. Adults spent more time in the open and in association with mountain mahogany (Cercocarpus montanus), while juveniles were more frequently found in association with dead wood, grass, and juniper (Juniperus monosperma). Adults also moved greater distances than juveniles and made use of larger areas. Movement patterns differed between age classes, with adults having longer step lengths. Adults and juveniles also engaged in different step length–turn angle sequences. For both classes, movement characteristics differed with habitat type.