Hi, I'm Stella. I'm a postdoctoral researcher with the Forest Park Living Lab,  via the Living Earth Collaborative at Washington University in St. Louis.  My postdoctoral research is on the community movement ecology of wildlife in Forest Park, a spectacular park in the heart of St. Louis

I'm particularly interested in why predators eat what they do and as much as they do, and how this depends on the predator's traits, community, and environment. I've worked with everything from protists to spiders to birds, although I have developed a particular fondness for owls. 

I completed my PhD in the DeLong lab at the University of Nebraska

Wanna chat? Contact me at stellauiterwaal@gmail.com or find me on ResearchGate, Twitter, or iNaturalist.


"Astrid", one of the Great Horned Owls in Forest Park, St. Louis. We are studying the movement, diet, and health of Astrid and other wildlife in Forest Park, including raccoons, coyotes, waterbirds, hawks, and turtles via the Forest Park Living Lab, in collaboration with Washington University in St. Louis, Saint Louis University, Saint Louis Zoo, National Great Rivers Research and Education Center, and the World Bird Sanctuary. Astrid was the first Forest Park raptor to be fitted with a GPS transmitter, and we have since tagged many more! Read more about the project here.

A male Tree Swallow with food provisioned for his nestlings. We are starting an exciting project at Cedar Point Biological Station to understand how prey diversity and availability affects the space use of breeding adults swallows. To do this, we are using the Motus Wildlife Tracking System, an international, collaborative network designed to study the movement patterns of aerial animals.

An iridescent blue and white Tree Swallow with prey in its beak being held while banding
A close up of a nestling barn owl's face. The owl is covered in down and is being held in front of a blue sky and green prairie background

Banding nestling Barn Owls. This year, we are putting GPS tags on breeding owls, live-trapping rodents, and dissecting owl pellets to examine how owls use the landscape to their advantage when hunting for their offspring.  

Gut content samples ready for DNA extraction and eventual metabarcoding to determine what prey the predators consumed. To quantify this type of data, half-lives can be used to describe how long prey DNA is detectable in the predator, but these half-lives are typically found using resource-intensive feeding trials. We show how these half-lives can be predicted and present a new method for improved metabarcoding quantification in our paper in Molecular Ecology Resources

Epi tubes with pink numbers arranged in a tray, viewed from above.
A scatter plot of consumer mass and handling time, showing that handling time decreases with mass

FoRAGE is our publicly-available, ever-expanding database of functional responses. Our 2020 meta-analysis of FoRAGE in Ecology confirmed known effects of predator and prey mass, revealed optimum foraging temperatures, and showed that dimensionality and taxonomic identity can profoundly influence functional responses. We are always adding to FoRAGE, so please do contact me with new functional responses!

Paramecium caudatum, an approximately 0.15 mm long protist and the subject of our 2020 study in Ecology and Evolution. We exposed replicate populations  to either a constant temperature or temperature fluctuations and to either predation or no predation. Our study revealed that these challenges produce conflicting  selective pressures and that responses to these pressures are constrained by trade-offs between cell morphology and thermal performance. 

Photo by Miranda Salsbery.

A photograph of Paramecium caudatum, a long, oval protist that appears greenish in this picture
A brown wolf spider in a glass respirometry tube being held in front of a grey background

Hogna wolf spider in a respirometry vial as part of our 2019 study in Ecological Entomology. As the spider respires, the oxygen concentration in the air-tight vial decreases. The sensor spot at the bottom of the vial detects these changes over time when the vial is placed in a respirometer. Our study shows that spiders with bigger opisthosoma (abdomens) - indicative of recent foraging success - have higher respiration rates for their size.

Still from a video of Drosophila melanogaster walking in arenas of different sizes. Using tracking software, we followed individuals' paths and found that the flies - and their predators - preferentially stayed near arena edges. Our 2019 study in Behavioral Ecology describes how this behavior, called thigmotaxis, causes arena size to have a pervasive effect on predation rates.

A still from a black and white video showing the location of flies in circular arenas
An close up photograph of ladybugs, spiders, and other arthropods on green vegetation with pink flowers

Lady beetles from an alfalfa field, including the native Hippodamia convergens (upper right) and the invasive Harmonia axyridis (lower right). Because they are a common biocontrol agent, there is an abundance of predation literature focused on lady beetles. Our 2018 meta-analysis of this literature reveals that arena size has a large impact on the outcomes of predation experiments with lady beetles. This critical finding suggests that pest management decisions can be misinformed if laboratory experiments do not take arena size into account. Published in the Journal of Applied Ecology.

A Bold Jumping Spider (Phidippus audax ) with its prey, a Salt Marsh Moth (Estigmene acrea) on a window at Cedar Point Biological Station in western Nebraska. See the iNaturalist observation for this photo here and here.

A black jumping spider with green chelicera, holding an orange and white moth with black spots, clinging to a window that reflects the blue sky and green trees behind.
An overhead view of a lime green damselfly nymph sitting in shallow water in a Petri dish, with the number 49 written in pencil on the paper below.

Damselfly nymph from our 2017 study in Oecologia. Damselflies are voracious generalist predators, and in our experiment we fed them Daphnia, copepods, and Chydorus. We found that, across all three prey types, nymphs forage best at an intermediate predator:prey size ratio.  This was also our first study where we found evidence that experimental arena size (in our case, Petri dish size) plays an important role in determining predation rates.