In 2019, our lab and Trevor Hefley in Statistics were funded from NSF to study the population biology of grassland birds at the Konza Prairie. This effort integrates our individual-level physiological data, population demographic studies, movement data, and the long-term survey data to understand the relative importance of local factors vs. regional and continental factors in shaping the abundance of this declining guild, and disentangle the direct and indirect effects of precipitation on this systems.

We collected our first summer’s data in 2019 and hope that the global pandemic does not completely ruin our chances of collecting at least the banding and resighting data so crucial to demographic studies.  This project builds on related research ongoing since 2013 but adds two additional species to our project. We are now focusing on three core grassland-dependent songbirds for individual-level and population-level studies (Grasshopper Sparrow, Dickcissel, and Eastern Meadowlark). Additionally, we will model the responses of the broader community in some of our analyses. Graduate students Katy Silber and Dylan Smith (Boyle lab) and Meenu Mohankumar (Hefley lab) are all involved in this project.

We are extremely grateful for support from the National Science Foundation (DEB-1754491) that makes this research possible.

ExpandClose

Work elsewhere has shown that songbird development is flexible in the face of predation risk. Another major selective pressure on nestlings and their parents is brood parasitism by Brown-headed Cowbirds. What are the direct and indirect effects of parasitism risk on nestling development and parental allocation?


This is the topic of Sarah Winnicki’s MS research. She studyied the effects of Brown-headed Cowbird (Molothrus ater) brood parasitism on the growth and development of nestlings of three grassland-obligate host species: Grasshopper Sparrow (Ammodramus savannarum), Dickcissel (Spiza americana), and Eastern Meadowlark (Sturnella magna). Using a combination of nest cameras, nestling measurements, and comparative analyses, we related skeletal growth, development (eyes opening, movement capacity), feather growth, and fat/muscle gain of the host nestlings to parasitism, predation, and parental feeding behavior. She also examined how being raised in the nests of different hosts affected cowbird nestling development. Sarah defended her thesis over the summer of 2019 and is preparing two manuscripts for publication. Stay tuned for the punchlines…!

ExpandClose

One of the best things about working at Kansas State University is access to the nearby Konza Prairie Biological Station. This site has been an LTER site since 1980 with bird data dating to 1981.


In 2017, Alice assumed responsibility for collecting long-term breeding bird transect data. In 2016, she also initiated a new monitoring effort of the winter bird community and spring passage migrants. Unlike the breeding bird data, this new effort uses mark-recapture on permanent plots to assess demographic parameters, and provides an excellent platform for student training, physiological studies, and outreach.

ExpandClose

Too little rain is a serious problem; consequently, the morphology and behavior of animals inhabiting arid regions is often defined by coping mechanism for low precipitation. But does enough rain eventually become too much rain? Read our recent conceptual synthesis and review on Hygric Niches for Tropical Endotherms or check out this introductory explainer video.

Mounting evidence from the tropics suggests that at the wet end of the spectrum, higher-than-average rainfall may decrease fitness. Using seven years of capture data from a community of birds in the mountains of Costa Rica, we showed that a wetter-than-average year can be negatively associated with apparent survival, but the responses are species-specific… not all birds respond to rainfall variation in the same ways, even in the same communities. We are testing multiple predictions of this hypothesis in our tropical system working in multiple populations of Corapipo altera across precipitation gradients on both the Caribbean and Pacific slope. Elsie Shogren conducted population-intensive studies of social stability and individual condition at Volcán Tenorio National park (in some of the driest Caribbean-slope forests inhabited by White-ruffed Manakins) while past work has also taken place at El Copal, a private reserve in the Reventazón valley and Rara Avis where Alice did her PhD work. We have collected data from five additional populations elsewhere in Costa Rica, adding tests of genomic predictions to this study.

Additionally, this question underlies some of our collaborative work with members of the Manakin Genomics Research Collaboration Network.

ExpandClose

Grassland birds have a reputation for being less predictable than their relatives living in forested environments. What kinds of movements do they make? Why do they make them? Why do some populations and individuals exhibit high site fidelity while so many others are never seen again?


Mid-continental grasslands are some of the most variable environments on earth. Within and between years, conditions bird experience can vary tremendously because grasslands are maintained by multiple natural disturbance processes. Fire and grazing by large ungulates have shaped this system for millennia, and along with high variability in annual rainfall, vegetation structure and prey communities are patchy mosaics in space and time. It is hardly surprising then that grassland-dependent birds are incredibly mobile, combining annual migrations with flexible settlement decisions that lead to high rates of breeding dispersal within and among years. We focus on Grasshopper Sparrows for this work, a species in which some populations have breeding-season return rates of over 70%, and others of 0%. At the Konza Prairie Biological Station, 16-22% of breeding males return from year to year, allowing us to (a) determine the individual-level correlates of site fidelity, and (b) examine the drivers of inter-annual variation in this behavior.

In our very first year studying these sparrows, we discovered that a remarkable number of them dispersed to new territories mid-way through the breeding season! Emily Williams tackled this pattern during her MS research (read Emily’s MSc thesis!). In her research, she (a) comprehensively described the patterns and spatial scales of within-season dispersal (Williams & Boyle, 2018), (b) tested predation- and parasitism-risk avoidance hypotheses to explain which individuals remained site-faithful and which dispersed (Williams & Boyle, 2019), and (c) tested the role of food availability in shaping the post-dispersal settlement decisions.

Here is a visual summary of the patterns reported in our within-season dispersal paper:

Meanwhile, we have also been determining the spatial scales of between-year dispersal movements for Konza-breeding Grasshopper Sparrows using stable isotopes, and discovering some remarkable things about site fidelity, birds skipping years but then returning, and wintering locations. There are many more mysteries to figure out in this system!

ExpandClose

Watch these manakins displaying! and copulating! Now… how on earth do those males DO that? What happens during that last incredible dive from above the canopy? How do they make those sounds?


In a current collaboration with Lainy Day, we used high-speed videography to answer these questions! We captured multiple displays of several males of varying ages and attractiveness to females. We think we know how the sounds are made now, and are on a quest to determine what makes a good display. This work builds upon interest in the White-ruffed Manakin breeding system which is characterized by remarkable variability in every aspect we’ve studied.

ExpandClose