Research interests



My interests in evolutionary behavioral ecology are centered on the influence of developmental stressors (often human-induced) on the ecology and evolution of wildlife


zebra finches



The major question that has stimulated most of my research is centered on the role of environmental stressors in moderating ecological and evolutionary change—a question of growing importance as anthropogenic stressors on natural populations continue to increase. I started this exploration by exploring the role of environmental developmental stressors on visual communication, mating, competitive, and anti-predatory behaviors in birds and insects. Subsequently, I expanded my research program to include an explicit conservation angle to study how anthropogenic environmental disturbance (e.g. land use change and noise pollution) affects breeding performance and behavioral strategies in song birds. I have also forged links between ecological and biodiversity principles with public health.

Land use change
Anthropogenic alteration of the environment is increasing and will not be reversed any time soon, hence it is important to understand how land use change affects wildlife populations. Specifically, I have spent the past decade understanding how conversion of lands to various forms of supposedly lower impact but economically viable use, such as golf courses, affects bird populations. Many wildlife ecologists are concerned about golf courses in particular as they may function as ecological traps—areas that attract wildlife but decrease viability of individuals living on these habitats. So far our work has shown that golf courses can be productive habitat for some bird species, including those that were of conservation concern just a few decades ago. Additionally, we are in the process of analyzing land use within golf courses and how sub-elements of courses support breeding and post-fledgling survival of songbirds. Our general approach can be applied to any form of “green” land use for new research projects; such a framework is paramount to understanding the utility of patches in a landscape of potential breeding and over-wintering habitats in contrast with unsupportive and/or damaging matrix. This type of question is particularly timely in assessing the biological and economic value (i.e. ecosystem service, in its broad interpretation) of urban green space.

In concert with land conversion (e.g. to golf courses), I have also investigated the effects of direct disturbance (vehicles, pedestrians, domestic animals, etc…) on the behavior and reproductive output of songbirds. This work illustrates that it is the unpredictability of the disturbance, as opposed to its particular source or magnitude (which is the prevailing dogma in much of the literature) which is most detrimental to the songbird species I have studied. Hence, managing the predictability of disturbance may permit for a compromise between increased human activities and maintaining wildlife population productivity. I would like to continue similar fieldwork, taking the work performed so far to generate specific hypotheses about disturbance-management practices and monitoring their effects.

Noise pollution
Introduction of anthropogenic noise can cause substantial behavioral problems for wildlife (e.g. blocking vocal communication channels for birds). To date, my work has shown that adult birds’ and nestlings’ vocal communication is disrupted by human noise pollution and that this can result in decreased strength of pair bonds and lower reproductive success. Although there is a fair amount known about how loud noises affect the physiology and development of humans, very little is known about how this prevalent form of pollution affects similar processes in wildlife. Here's a short video produced by Jamie Hall ('13) and Conor MacDonnell ('14) (as part of a science film-making class taught by Jes Therkelsen) about noise pollution:

I am collaborating with Prof Mark Hinders in the Applied Science department at William and Mary to develop highly directional speaker arrays that produce noise that blocks communication among birds, making areas acoustic unsuitable for birds. When birds are under these "sonic nets" their vigilance sky rockets as they can't hear predator cues. This leads to long-term deterrence that doesn't seem to diminish over time. We are developing this technology as a sustainable way to exclude pest bird species from places where birds cause damage (e.g. farms, vineyards, airports) and where birds can be damaged themselves (e.g. contaminated areas, solar farms). So far, our work indicates that our "sonic nets" can effectively exclude birds from food areas and from airfields. Our Advancement Office made a short video about this sonic net project. I also gave a short TEDx talk about these ideas.

In another application of birds' sensory ecology, we have also developed and tested a way of using sound to limit birds' collisions with human-made objects such as buildings, communication towers, and wind turbines. Our "acoustic lighthouse" concept uses a conspicuous sounds as a warning device to make birds may more attention to where they are flying. Initial tests have been very successful--greatly reducing the velocity of birds as they approach a potential strike surface and even leading to avoiding the object altogether.

Ecology, biodiversity, and public health
We have investigated the consequences of avian ecology and diversity for human health. We have collected robust information to indicate that humans are often better protected against avian-borne diseases (e.g. West Nile virus) when avian biodiversity increases in local populations. This is because most avian species are poor host reservoirs for their respective disease organisms, and so adding a bird species to an area most likely adds a low competence host and “dilutes” the disease locally, lowering infection risks for humans. We are currently expanding this project by looking at further ways in which wildlife community structure and life history traits influence infectious disease risks to humans.

Another of our current projects relates ecology with public health. We are investigating how low levels of mercury exposure influence many aspects of individual physiology (cellular immune responses, adreno-coriticol responses) development (neural formation, brain language center development) and behavior (mate preferences, male song, flight mechanics, foraging strategy, antipredatory tactics) in two model songbird species (zebra finches, European starlings). Mercury is a global, persistent contaminant that is released in large amounts from certain chemical processes and coal-fired power plants, and biomagnifies and accumulates in aquatic and terrestrial food webs. Little is known about how low-level exposure to mercury affects key systems in the body and the published “safe levels” are largely driven by litigation rather than strong science. We are performing the first long-term study of how mercury disrupts cellular and organismal processes in terrestrial birds. We have already noticed that there are substantial and consistent among-individual differences in susceptibility to mercury which we would like to investigate by genetic and genomic studies; merging evolutionary biology with ecotoxicology. We are particularly excited about our new project, investigating the effects of mercury on male fertility and could help to explain falling sperm counts around the globe.

Watch our short mercury project video that gives a general overview (there's a 10sec lag at the beginning, so be patient).

Links to other research sites for John's work:

LinkedIn Academia dot eduresearch gate


©Copyright John Swaddle, Biology Department, College of William and Mary
Last updated August 7, 2017