MCA Pilot PUI: Can unhatched eggs or trash affect nestling development and survival via modified thermal properties of the nest?

Lafayette College, Easton PA

Investigators

Abstract

Songbird populations are dwindling, so it is important to understand how the conditions animals experience early in life affect how big they grow, how fast they grow, and whether they are likely to survive. Studying these experiences provides important biological insights and informs questions related to managing wildlife species that are either a conservation priority or are invasive, or managing game populations. As animals more frequently interact with humans, there is also an increased need to study the effects that people have on their survival. To address these questions in part, this project will examine how different amounts of trash in the nests of a songbird species and the number of eggs in the nest affect the parents’ ability to incubate eggs and keep baby birds warm. Then, this project will link nest temperatures with the baby birds’ ability to grow quickly enough, to large enough sizes, and to survive. Accomplishing this goal will require the development of new technology, including miniaturized temperature sensors that can be hidden within 3D-printed eggs. These temperature-sensing devices can be twice as sensitive as commercially available options, fit into much smaller egg models, and be produced for less than half the price than earlier technology. The development of this technology could then influence industries that track temperatures of goods, and the biological lessons could be important for those involved in the bird-watching industry, which generates approximately $100 billion annually. The tools developed in this project will also be deployed in classroom and mentored research setting with undergraduates. When an individual invests in parental effort, this effort provides benefits to young but reduces the resources available to current or future offspring. Thus, when females lay eggs that do not hatch, that behavior is deemed costly due to the expenditure of resources (e.g., allocating nutrients to the egg, investing energy to incubate the egg), with no perceived fitness benefit in terms of additional offspring. However, it is possible that not all hatching failure has negative fitness consequences. If parents can construct thermally efficient nests, the cost of producing and incubating an extra egg may result in proportionately greater benefits later on, when developing offspring can rely upon the thermal inertia of an unhatched egg to maintain a higher body temperature, even when they cannot thermoregulate themselves. Additionally, some birds incorporate trash into their nests, which could affect the nest’s thermal properties. By 1) evaluating nest characteristics, and 2) developing the next generation of dataloggers to measure incubation behavior, it will be possible to evaluate how trash content within a nest and the presence of unhatched eggs interact to affect temperature within a nest. By using urban-exploiting house sparrows (Passer domesticus) as a model species, which routinely incorporate trash into their nests, it will be possible to evaluate how within-nest temperatures are related to nestling growth, survival, and condition throughout development. By also tracking juvenile behavior using Radio Frequency Identification (RFID)-based tracking methods, this project will also evaluate longer-term consequences of nest environment and parental effort. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.