Animal Sciences Commons^™

Sex Ratio Is Variable And Increasingly Male Biased At Two Colonies Of Magellanic Penguins, Natasha J. Gownaris, Pablo García Borboroglu, P. Dee Boersma

Environmental Studies Faculty Publications

Sex ratios are commonly skewed and variable in wild populations, but few studies track temporal trends in this demographic parameter. We examined variation in the operational sex ratio at two protected and declining breeding colonies of Magellanic Penguins (Spheniscus magellanicus) in Chubut, Argentina. Penguins from the two colonies, separated by 105 km, migrate north in the non‐breeding season and have overlapping distributions at sea. Conditions during the non‐breeding season can impact long‐term trends in operational sex ratio (i.e., through sex‐specific survival) and interannual variation in operational sex ratio (i.e., through sex‐specific breeding decisions). We found an increasingly male‐biased …

The Traits That Predict The Magnitude And Spatial Scale Of Forest Bird Responses To Urbanization Intensity, Grant D. Paton, Alexandra V. Shoffner, Andrew M. Wilson, Sara A. Gagné

Environmental Studies Faculty Publications

As humans continue moving to urban areas, there is a growing need to understand the effects of urban intensification on native wildlife populations. Forest species in remnant habitat are particularly vulnerable to urban intensification, but the mechanisms behind these effects are poorly understood. An understanding of how species traits, as proxies for mechanisms, mediate the effects of urban intensification on forest species can help fill this knowledge gap. Using a large point count dataset from the Second Pennsylvania Breeding Bird Atlas, we tested for the effects of species traits on the magnitude and spatial scale of the responses of 58 …

Sex‐Biased Survival Contributes To Population Decline In A Long‐Lived Seabird, The Magellanic Penguin, Natasha J. Gownaris, P. D. Boersma

Environmental Studies Faculty Publications

We developed a Hidden Markov mark–recapture model (R package marked) to examine sex‐specific demography in Magellanic Penguins (Spheniscus magellanicus ). Our model was based on 33 yr of resightings at Punta Tombo, Argentina, where we banded ~44,000 chicks from 1983 to 2010. Because we sexed only 57% of individuals over their lifetime, we treated sex as an uncertain state in our model. Our goals were to provide insight into the population dynamics of this declining colony, to inform conservation of this species, and to highlight the importance of considering sex‐specific vital rates in demographic seabird studies. Like many other …

The Relative Effects Of Forest Amount, Forest Configuration, And Urban Matrix Quality On Forest Breeding Birds, Alexandra V. Shoffner, Andrew M. Wilson, Wenwu Tang, Sara A. Gagné

Environmental Studies Faculty Publications

Urbanization modifies landscape structure in three major ways that impact avian diversity in remnant habitat: habitat amount is reduced and habitat configuration and matrix quality are altered. The relative effects of these three components of landscape structure are relatively well-studied in agricultural landscapes, but little is known about the relative effect of urban matrix quality. We addressed this gap by investigating the relative effects of forest amount, forest configuration, and matrix quality, indicated by degree of urbanization and agriculture amount, on the diversity of three guilds of forest birds using data from 13,763 point counts from Pennsylvania, USA. Forest amount …

Age-Specific Differences In Fat Reserves And Migratory Passage Of Setophaga Striata (Blackpoll Warbler), Emily N. Filiberti, Noah G. Perlut

Environmental Studies Faculty Publications

Adequate fat reserves are vital for long non-stop transatlantic avian-migration movements, such as those made by Setophaga striata (Blackpoll Warbler). Over a 5-y period, we studied differences in preparedness (determined by presence of fat content and arrival time at stopover locations) between hatch-year (HY) and after hatch-year (AHY) Blackpoll Warblers at 3 stopover sites (Hancock and York counties in Maine, and Plymouth County in Massachusetts) covering 2.65° latitude along the Gulf of Maine. Migration timing varied across a latitudinal gradient and between age classes. In September, AHY Blackpoll Warblers were more abundant in the northern and central counties, but HY …

Spatial Models To Account For Variation In Observer Effort In Bird Atlases, Andrew M. Wilson, Daniel W. Brauning, Caitlin Carey, Robert S. Mulvihill

Environmental Studies Faculty Publications

To assess the importance of variation in observer effort between and within bird atlas projects and demonstrate the use of relatively simple conditional autoregressive (CAR) models for analyzing grid-based atlas data with varying effort. Pennsylvania and West Virginia, United States of America. We used varying proportions of randomly selected training data to assess whether variations in observer effort can be accounted for using CAR models and whether such models would still be useful for atlases with incomplete data. We then evaluated whether the application of these models influenced our assessment of distribution change between two atlas projects separated by twenty …

The Feasibility Of Counting Songbirds Using Unmanned Aerial Vehicles, Andrew M. Wilson, Janine M. Barr, Megan E. Zagorski

Environmental Studies Faculty Publications

Obtaining unbiased survey data for vocal bird species is inherently challenging due to observer biases, habitat coverage biases, and logistical constraints. We propose that combining bioacoustic monitoring with unmanned aerial vehicle (UAV) technology could reduce some of these biases and allow bird surveys to be conducted in less accessible areas. We tested the feasibility of the UAV approach to songbird surveys using a low-cost quadcopter with a simple, lightweight recorder suspended 8 m below the vehicle. In a field experiment using playback of bird recordings, we found that small variations in UAV altitude (it hovered at 28, 48, and 68 …

Seismic Surveys And Marine Turtles: An Underestimated Global Threat?, Sarah E. Nelms, Wendy Dow Piniak, Caroline R. Weir, Brendan J. Godley

Environmental Studies Faculty Publications

Seismic surveys are widely used in marine geophysical oil and gas exploration, employing airguns to produce sound-waves capable of penetrating the sea floor. In recent years, concerns have been raised over the biological impacts of this activity, particularly for marine mammals. While exploration occurs in the waters of at least fifty countries where marine turtles are present, the degree of threat posed by seismic surveys is almost entirely unknown. To investigate this issue, a mixed-methods approach involving a systematic review, policy comparison and stakeholder analysis was employed and recommendations for future research were identified. This study found that turtles have …

Sustaining The Saco Estuary: Final Report 2015, Christine B. Feurt Ph D, Pamela A. Morgan, Mark D. O. Adams, Anna L. Bass, Carrie J. Byron, Michael C. Daley, Michael O. Esty, Noah G. Perlut, Kayla Smith, Tyler Spillane, Michelle M. Steen-Adams, James Sulikowski, Stephan I. Zeeman, Jacob Aman, Michele Dionne, Jeremy Miller, Kristin Wilson

Environmental Studies Faculty Publications

This study focuses on the Saco estuary, the tidal portion of the Saco River, which drains the largest watershed in southern Maine. With headwaters in the White Mountains of New Hampshire, the watershed encompasses more than 4,400 km², and provides clean healthy drinking water to over 100,000 people living and working in communities in southern Maine.

When the study began in 2009, very little was known about the ecology of the Saco estuary. Researchers at the University of New England and the Wells National Estuarine Research Reserve employed the process of collaborative learning to bring together people who …

Recruitment Facilitation And Spatial Pattern Formation In Soft-Bottom Mussel Beds, John A. Commito, Ann E. Commito, Rutherford V. Platt, Benjamin M. Grupe, Wendy Dow Piniak, Natasha J. Gownaris, Kyle A. Reeves, Allison M. Vissichelli

Environmental Studies Faculty Publications

Mussels (Mytilus edulis) build massive, spatially complex, biogenic structures that alter the biotic and abiotic environment and provide a variety of ecosystem services. Unlike rocky shores, where mussels can attach to the primary substrate, soft sediments are unsuitable for mussel attachment. We used a simple lattice model, field sampling, and field and laboratory experiments to examine facilitation of recruitment (i.e., preferential larval, juvenile, and adult attachment to mussel biogenic structure) and its role in the development of power-law spatial patterns observed in Maine, USA, soft-bottom mussel beds. The model demonstrated that recruitment facilitation produces power-law spatial structure similar …