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Ornithology

Andrews University

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Full-Text Articles in Life Sciences

A Note On The Onset Of Synchronous Egg Laying In A Seabird Behavior Model, Dorothea Gallos, Christiane Gallos Apr 2018

A Note On The Onset Of Synchronous Egg Laying In A Seabird Behavior Model, Dorothea Gallos, Christiane Gallos

Honors Theses

Protection Island, Washington hosts a large colony of Glaucous-winged gulls (Larus glaucescens). These birds are known to exhibit every-other-day egg-laying synchrony in dense areas of the colony in response to egg cannibalism, which is the main source of egg loss. Here we present an equilibrium analysis of a discrete-time animal behavior model for egg laying. We use Jury Conditions to find the stability criteria for the equilibrium as a function of the colony density and show that a 2-cycle bifurcation occurs when the equilibrium loses stability. The 2-cycle pattern in egg laying becomes increasingly synchronous as the colony density increases. …

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Effects Of Eggshell Coloration On Egg Cannibalism Among Glaucous-Winged Gulls, Isabelle Hwang Apr 2018

Effects Of Eggshell Coloration On Egg Cannibalism Among Glaucous-Winged Gulls, Isabelle Hwang

Honors Theses

A common source of reproductive loss in gulls is egg cannibalism. At a large Glaucous-winged Gull (Larus glaucescens) colony on Protection Island, Washington, cannibalism accounts for 55% of egg loss. Because cannibalism is a form of predation and birds have a highly developed sense of vision, I hypothesized that visible light coloration of Glaucous-winged Gull eggs plays a role in determining whether they are cannibalized. I used logistic regression to test whether egg fate was related to egg brightness, specific coloration, specific spot coverage, coloration relative to the most common coloration, and spot coverage relative to the most common spot …

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P-46 A Periodic Matrix Model Of Seabird Behavior And Population Dynamics, Mykhaylo M. Malakhov, Benjamin Macdonald, Shandelle M. Henson, J. M. Cushing Mar 2018

P-46 A Periodic Matrix Model Of Seabird Behavior And Population Dynamics, Mykhaylo M. Malakhov, Benjamin Macdonald, Shandelle M. Henson, J. M. Cushing

Honors Scholars & Undergraduate Research Poster Symposium Programs

Rising sea surface temperatures (SSTs) in the Pacific Northwest lead to food resource reductions for surface-feeding seabirds, and have been correlated with several marked behavioral changes. Namely, higher SSTs are associated with increased egg cannibalism and egg-laying synchrony in the colony. We study the long-term effects of climate change on population dynamics and survival by considering a simplified, cross-season model that incorporates both of these behaviors in addition to density-dependent and environmental effects. We show that cannibalism can lead to backward bifurcations and strong Allee effects, allowing the population to survive at lower resource levels than would be possible otherwise.

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Time Lags Associated With Effects Of Oceanic Conditions On Seabird Breeding In The Salish Sea Region Of The Northern California Current System, Rashida S. Smith, Lynelle M. Weldon, James L. Hayward, Shandelle M. Henson Apr 2017

Time Lags Associated With Effects Of Oceanic Conditions On Seabird Breeding In The Salish Sea Region Of The Northern California Current System, Rashida S. Smith, Lynelle M. Weldon, James L. Hayward, Shandelle M. Henson

Faculty Publications

No abstract provided.

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Data For Henson Et Al. 2016, Shandelle Henson, James Hayward, J Cushing, Gordon Atkins, Sumiko Weir, Ashley Reichert, Wayanne Watson, Wadenerson Saint Martin, Amanda Sandler Jan 2016

Data For Henson Et Al. 2016, Shandelle Henson, James Hayward, J Cushing, Gordon Atkins, Sumiko Weir, Ashley Reichert, Wayanne Watson, Wadenerson Saint Martin, Amanda Sandler

Faculty Publications

These data are archived for the paper "Adaptation to short-term ENSO fluctuations may provide tipping points for populations subjected to long-term climate change" by Henson et al., submitted. Additional files: Supplementary Figure 1 | Sample plots on Violet Point, Protection Island National Wildlife Refuge, Washington, USA. The larger colony extends throughout much of the spit.

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Henson Et Al Supplementary Figure 1.Pdf, Shandelle Henson Jan 2016

Henson Et Al Supplementary Figure 1.Pdf, Shandelle Henson

Faculty Publications

Supplementary Figure 1 | Sample plots on Violet Point, Protection Island National WildlifeRefuge, Washington, USA. The larger colony extends throughout much of the spit.

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Data For Henson Et Al. 2016, Shandelle M. Henson, James L. Hayward, J M. Cushing, Gordon Atkins, Sumiko K. Weir, Ashley A. Reichert, Wayanne Watson, Wadenerson Saint Martin, Amanda Sandler Jan 2016

Data For Henson Et Al. 2016, Shandelle M. Henson, James L. Hayward, J M. Cushing, Gordon Atkins, Sumiko K. Weir, Ashley A. Reichert, Wayanne Watson, Wadenerson Saint Martin, Amanda Sandler

Shandelle M. Henson

These data are archived for the paper "Adaptation to short-term ENSO fluctuations may provide tipping points for populations subjected to long-term climate change" by Henson et al., submitted.
Additional files:
Supplementary Figure 1 | Sample plots on Violet Point, Protection Island National WildlifeRefuge, Washington, USA. The larger colony extends throughout much of the spit.

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Data For Sandler Et Al. 2015, Amanda Sandler, Libby Megna, James Hayward, Shandelle Henson, Cynthia Tkachuck, Richard Tkachuck Jan 2015

Data For Sandler Et Al. 2015, Amanda Sandler, Libby Megna, James Hayward, Shandelle Henson, Cynthia Tkachuck, Richard Tkachuck

Faculty Publications

These data are archived for the paper "Every-other-day clutch-initiation synchrony in ring-billed gulls (Larus delawarensis)" by Sandler et al., submitted

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Data For Sandler Et Al. 2015, Amanda G. Sandler, Libby C. Megna, James L. Hayward, Shandelle M. Henson, Cynthia M. Tkachuck, Richard D. Tkachuck Jan 2015

Data For Sandler Et Al. 2015, Amanda G. Sandler, Libby C. Megna, James L. Hayward, Shandelle M. Henson, Cynthia M. Tkachuck, Richard D. Tkachuck

Shandelle M. Henson

These data are archived for the paper "Every-other-day clutch-initiation synchrony in ring-billed gulls (Larus delawarensis)" by Sandler et al., submitted

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Data For Henson Et Al. 2014, Shandelle M. Henson, James L. Hayward, Gordon Atkins, Amanda Sandler, Wadenerson Saint Martin Nov 2014

Data For Henson Et Al. 2014, Shandelle M. Henson, James L. Hayward, Gordon Atkins, Amanda Sandler, Wadenerson Saint Martin

Faculty Publications

These data are archived for the paper "Changing sea surface temperature alters timescale of reproductive synchrony in seabirds" by Henson et al., currently submitted to Nature.

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Socially Induced Ovulation Synchrony And Its Effect On Seabird Population Dynamics, Shandelle M. Henson, J. M. Cushing, James L. Hayward Sep 2011

Socially Induced Ovulation Synchrony And Its Effect On Seabird Population Dynamics, Shandelle M. Henson, J. M. Cushing, James L. Hayward

Faculty Publications

Spontaneous oscillator synchrony is a form of self-organization in which populations of interacting oscillators ultimately cycle together. This phenomenon occurs in a wide range of physical and biological systems. In rats and humans, oestrous/menstrual cycles synchronize through social stimulation with pheromones acting as synchronizing signals. In previous work, we showed that glaucous-winged gulls (Larus glaucescens) can lay eggs synchronously on an every-other-day schedule, and that synchrony increases with colony density. We posed a discrete-time mathematical model for reproduction during the breeding season based on the hypothesis that pre-ovulatory luteinizing hormone surges synchronize by means of visual, auditory and/or olfactory cues. …

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Foraging-Related Activity Of Bald Eagles At A Washington Seabird Colony And Seal Rookery, James L. Hayward, Joseph G. Galusha, Shandelle M. Henson Mar 2010

Foraging-Related Activity Of Bald Eagles At A Washington Seabird Colony And Seal Rookery, James L. Hayward, Joseph G. Galusha, Shandelle M. Henson

Faculty Publications

From 1980 to 1998, Washington's Bald Eagle (Haliaeetus leucocephalus) population increased at an annual rate of 10. Over the same time period, foraging activity of Bald Eagles at marine bird breeding colonies also increased. From 1993 to 2008, we observed foraging-related behavior of Bald Eagles on Violet Point, Protection Island. This island hosts more than 70 of the breeding seabirds in Washington's inner seaways and serves as an important rookery for harbor seals (Phoca vitulina). We found that (1) eagles landed more frequently in seal haul-out (beach) areas than in gull-nesting (non-beach) areas of Violet Point, and that subadult eagles …

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Socially Induced Synchronization Of Every-Other-Day Egg Laying In A Seabird Colony, Shandelle M. Henson, James L. Hayward, J. M. Cushing, Joseph C. Galusha Jan 2010

Socially Induced Synchronization Of Every-Other-Day Egg Laying In A Seabird Colony, Shandelle M. Henson, James L. Hayward, J. M. Cushing, Joseph C. Galusha

Faculty Publications

Spontaneous oscillator synchrony has been documented in a wide variety of electrical, mechanical, chemical, and biological systems, including the menstrual cycles of women and estrous cycles of Norway Rats (Rattus norvegicus). In temperate regions, many colonial birds breed seasonally in a time window set by photoperiod; some studies have suggested that heightened social stimulation in denser colonies can lead to a tightened annual reproductive pulse. It has been unknown, however, whether the analog of menstrual synchrony occurs in birdsthat is, whether avian ovulation cycles can synchronize on a daily timescale within the annual breeding pulse. We report every-other-day clutch-initiation and …

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Modeling The Daily Activities Of Breeding Colonial Seabirds: Dynamic Occupancy Patterns In Multiple Habitat Patches, Andrea L. Moore, Smruti P. Damania, Shandelle M. Henson, James L. Hayward Oct 2008

Modeling The Daily Activities Of Breeding Colonial Seabirds: Dynamic Occupancy Patterns In Multiple Habitat Patches, Andrea L. Moore, Smruti P. Damania, Shandelle M. Henson, James L. Hayward

Faculty Publications

We constructed differential equation models for the diurnal abundance and distribution of breeding glaucous-winged gulls (Larus glaucescens) as they moved among nesting and non-nesting habitat patches. We used time scale techniques to reduce the differential equations to algebraic equations and connected the models to field data. The models explained the data as a function of abiotic environmental variables with R2=0.57. A primary goal of this study is to demonstrate the utility of a methodology that can be used by ecologists and wildlife managers to understand and predict daily activity patterns in breeding seabirds.

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Habitat Patch Occupancy Dynamics Of Glaucous-Winged Gulls (Larus Glaucescens) I: A Discrete-Time Model, Karl W. Phillips, Smruti P. Damania, James L. Hayward, Shandelle M. Henson, Clara J. Logan Jan 2005

Habitat Patch Occupancy Dynamics Of Glaucous-Winged Gulls (Larus Glaucescens) I: A Discrete-Time Model, Karl W. Phillips, Smruti P. Damania, James L. Hayward, Shandelle M. Henson, Clara J. Logan

Faculty Publications

Diurnal habitat occupancy dynamics of Glaucous-winged Gulls were evaluated in a system of six habitats on and around Protection Island, Washington. Data were collected on the rates of gull movement between habitat patches, and from these data the probabilities of transitions between habitats were estimated as functions of tide height and time of day. A discrete-time matrix model based on the transition probabilities was used to generate habitat occupancy predictions, which were then compared to hourly census data. All model parameters were estimated directly from data rather than through model fitting. The model made reasonable predictions for two of the …

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Habitat Patch Occupancy Dynamics Of Glaucous-Winged Gulls (Larus Glaucescens) Ii: A Continuous-Time Model, Smruti P. Damania, Karl W. Phillips, Shandelle M. Henson, James L. Hayward Jan 2005

Habitat Patch Occupancy Dynamics Of Glaucous-Winged Gulls (Larus Glaucescens) Ii: A Continuous-Time Model, Smruti P. Damania, Karl W. Phillips, Shandelle M. Henson, James L. Hayward

Faculty Publications

The diurnal distribution and abundance dynamics of loafing Glaucous-winged Gulls (Larus glaucescens) were examined at Protection Island National Wildlife Refuge, Strait of Juan de Fuca, Washington. Asynchronous movement of gulls among three habitat patches dedicated to loafing was modeled as a function of environmental variables using differential equations. Multiple time scale analysis led to the derivation of algebraic models for habitat patch occupancy dynamics. The models were parameterized with hourly census data collected from each habitat patch, and the resulting model predictions were compared with observed census data. A four-compartment model explained 41% of the variability in the data. Models …

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Do Rhinoceros Auklet, Cerorhinca Monocerata, Fledglings Fly To The Sea From Their Natal Burrows?, James L. Hayward, Jere K. Clayburn Jan 2004

Do Rhinoceros Auklet, Cerorhinca Monocerata, Fledglings Fly To The Sea From Their Natal Burrows?, James L. Hayward, Jere K. Clayburn

Faculty Publications

The mode of departure of Rhinoceros Auklet fledglings from their nest burrows has remained uncertain. Both walk-down and fly-down hypotheses have been proposed. Here we use the unique geography of Protection Island, Washington, to evaluate the fly-down hypothesis. Some fledglings raised on Protection Island do appear to walk to the water, but our results suggest that many of the island's fledgling Rhinoceros Auklets fly to the sea.

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Predicting Dynamics Of Aggregate Loafing Behavior In Glaucous-Winged Gulls (Larus Glaucescens) At A Washington Colony, Shandelle M. Henson, James L. Hayward, Christina M. Burden, Clara J. Logan, Joseph G. Galusha Jan 2004

Predicting Dynamics Of Aggregate Loafing Behavior In Glaucous-Winged Gulls (Larus Glaucescens) At A Washington Colony, Shandelle M. Henson, James L. Hayward, Christina M. Burden, Clara J. Logan, Joseph G. Galusha

Faculty Publications

Seabirds move throughout the day in changing, patchy environments as they engage in various behaviors. We studied the diurnal abundance dynamics of Glaucous-winged Gulls (Larus glaucescens) in a habitat patch dedicated to loafing in the Strait of Juan de Fuca, Washington. We constructed three differential equation models as alternative hypotheses and then used model selection techniques to choose the one that most accurately described the system. We validated the model on an independent data set, made a priori model predictions, and conducted a field test of the predictions. Clear dynamic patterns emerged in the abundance of loafing gulls, even though …

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