Seminar: Ferruginous Hawk (Buteo regalis) responses to human disturbance during the breeding season

Here is a young female Ferruginous Hawk sporting her new bands.On the left leg (her right leg) is the field-readable colour band and the silver band with serial number is on the right leg. Photo: Janet Ng.

Ferruginous Hawk on a nest, photo by Janet Ng

Today (14 December 2015) Cameron Nordell will give a public seminar as part of his MSc thesis defense. Come hear about his research at 1pm in the University of Alberta Biological Sciences Building, room CW 313.

 

Talk Summary:

The expansion of the human footprint across the world is increasing the number of interactions between humans and wildlife. Many studies have quantified wildlife behavioural responses to humans and this is an active area of research with practical implications for species conservation. However, changes to individual animals behaviour may be influenced by the properties of the disturbance stimulus itself, the effect of the environment in which the interaction occurs, and the individual’s past experience, but these potentially important effects have rarely been evaluated. Additionally it is unclear how individuals behave in the hours following the departure of human disturbance. In southern Alberta and Saskatchewan, I quantified the flight initiations from the nest by Ferruginous Hawks (Buteo regalis) in response to approaching investigators and used digital video systems to quantify their behaviour following investigator departure.

In Chapter 2 I studied the flight initiation distance from the nest (FID) by adult Ferruginous Hawks. FID was related to the actions of the investigator, the anthropogenic landscape around the nest and the number of previous visits to Ferruginous Hawk nests by investigators. Approaches by humans on foot illicit longer FIDs than those in a vehicle. Approaches driving on private access roads that were infrequently used by vehicles were related to increased FID. My data show that shorter FIDs are related greater number of vehicles that pass near a nest, demonstrating a relationship between human disturbances around the nest and FID. Finally, Ferruginous Hawk FIDs increased as the number of previous investigator approaches to that nest increased. Chapter 2 highlights the dynamic and complex nature of the decision to initiate flight from the nest and provides new insight as to why FID varies between and within species.

Having explored factors influencing the Ferruginous Hawk’s decision to change behaviour in response to human disturbance in Chapter 2, Chapter 3 focuses on the behavioural consequence through time when disturbed by humans. Here, I used digital video footage of Ferruginous Hawk nests to document nesting behaviour of adult males and females up to 12 hrs following an investigator disturbance, and test non-exclusive hypotheses that may explain differences in behaviour relative to undisturbed control periods. On average, across the 12 hr sample period, female Ferruginous Hawk spent significantly less time on the nest following investigator disturbance relative to controls, but individual variation was high. Delivery of prey items to the nest not significant different between disturbance and control sample periods. Disturbed female time on nest, initially lower than control periods, returned to normal over the course of our 12 hr sample period. The duration of reduced time on nest by the female varied with age and number of nestlings, such that female time on nest returned to normal sooner following a disturbance for young nestlings, and with larger broods. Thus, I found support for both the harm-to-offspring and parental investment hypotheses. This is among the first studies to identify that disturbed animals demonstrate behavioural differences from normal for up to 12 hrs following disturbance.

The ability to adapt flight initiation behaviour to human approaches and the consistent delivery of prey when disturbed suggests that, Ferruginous Hawks nesting in the highly anthropogenic regions of southern Alberta and Saskatchewan demonstrate the behavioural plasticity necessary to coexist with some human disturbance to the nest site. However, I also found instances of Ferruginous Hawk flight initiation at large distances, and that some individuals reduced nest attendance for lengthy durations following a human disturbance. Understanding how these extreme behaviours affect reproductive success of Ferruginous Hawks is likely essential to understanding human impacts on the Ferruginous Hawk population in Canada. My research was intended to contribute to the ongoing conservation effort for this species, and I discuss potential implications for management in Chapter 4. My research provides novel insight into disturbed behaviour and can inform management policies in the future as human development in the grasslands ecoregions expands and increases the number of interactions between humans and Ferruginous Hawks.

Public Seminar: The use of citizen science to identify the factors affecting bird-window collisions at residential houses

On Tuesday, December 8, Justine Kummer will be presenting a public seminar for her MSc defence. Come hear about her research in the University of Alberta Biological Sciences Building room CW 313 at 1pm.

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Talk Summary

Every year a large number of birds die when they collide with windows. The actual number however is difficult to ascertain. Previous attempts to estimate bird-window collision rates in Canada relied heavily on a citizen science study that used memory-based surveys which may have potential biases. Building upon this study and their recommendations for future research the Birds and Windows citizen science project was designed to have homeowners actively search for collision evidence at their houses and apartments for an extended period. The first objective of the Birds and Windows project was to see how a more standardized approach to citizen science data collection influenced bird-window collision estimates and to see if the same patterns observed by memory-based surveys were observed using different data collection methods. Comparing the results from the Birds and Windows standardized searches and memory-based surveys revealed differences in absolute values of collisions but similar relative rankings between residence types. This suggests that memory-based surveys may be a useful tool for understanding the relative importance of different risk factors causing bird-window collisions.

The second objective from the Birds and Windows project was to gain a better understanding of the factors affecting collisions at residential houses. It currently remains poorly understood which types of buildings and windows are most problematic. Understanding whether neighbourhood type, yard conditions, house attributes, or window types have the largest effect on collision rates is crucial for identifying which mitigation options might be most effective. Factors at the yard level had the best model fit for predicting bird-window collisions at residential houses. Conservation efforts should target variables at this level and those factors that attract birds to an individual yard. As few homeowners are likely to take an approach that reduces the number of birds in their yards, focus should instead be given to bird-friendly urban design and developing the most effective window deterrents.

Finally, the effects of bird feeder presence and placement on bird-window collisions at residential homes was determined through a manipulative experiment. During the study there were 1.84 times more collisions when the bird feeder was present. However, there were no collisions at half of the study windows. High variance was observed in the number of collisions at different houses, indicating that effects of bird feeders are context dependent. Changing the occurrence, timing, and placement of feeders can alter collision rates but is only one of many factors that influence whether a residential house is likely to have a bird-window collision or not.

In conclusion, I provide recommendations for conducting future survey-based citizen science projects and outline the next steps for bird-window collision research in working towards stopping avian mortality from collisions with windows. I have thoroughly outlined a number of factors affecting bird-window collisions and the focus of future research should now shift towards reducing the problem. The Birds and Windows project saw a number of successes as a citizen science project and citizen science remains the best method for collecting large scale data in real-world scenarios and should continue to be used in similar experiments.

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Seminar: Projecting boreal bird responses to climate change: considering uncertainty, refugia, time lags, and barriers

Diana Stralberg will be presenting her thesis defense seminar on Tuesday, November 3 at 1pm in the University of Alberta Biological Sciences Building room CW313. Check out her abstract below.

Photo by Craig Machtans, Environment Canada.

Photo by Craig Machtans, Environment Canada.

Abstract: Often referred to as North America’s bird nursery, the boreal forest biome provides a resource-rich environment for breeding birds, supporting high species diversity and bird numbers. These birds are likely to shift their distributions northward in response to rapid climate change over the next century, resulting in population- and community-level changes. Using a new continental-scale avian dataset, I have developed models to project climate-induced changes in the distribution and relative abundance of 80 boreal-breeding passerine species. For such projections to be useful, however, the magnitude of change must be understood relative to the magnitude of uncertainty in model predictions. In my first chapter, I found that the mean signal-to-noise ratio across species increased over time to 2.87 by the end of the 21st century, with the signal greater than the noise for 88% of species. I also found that, among sources of uncertainty evaluated, the choice of climate model was most important for 66% of species, sampling error for 29% of species, and variable selection for 5% of species. In addition, the range of projected changes and uncertainty characteristics across species differed markedly, suggesting the need for a variety of approaches to climate change adaptation.

Species and ecosystems may be unable to keep pace with rapid climate change projected for the 21st century, however. In my second chapter, I evaluated an underexplored dimension of the mismatch between climate and biota: limitations to forest growth and succession affecting habitat suitability. I found that end-of-century projected changes in songbird distribution were reduced by up to 169% when vegetation lags were considered, indicating that limits to forest growth and succession may result in dramatic reductions in suitable habitat for many species over the next century. I used these results to identify conservative and efficient boreal conservation priorities anchored around climatic macrorefugia that are robust to century-long climate change and complement the current protected areas network.

Vegetation change may also be delayed in the absence of disturbance catalysts. In the western boreal region, a combined increase in wildfires and human activities may aid these transitions, also resulting in a younger forest. In my third chapter, I developed a hybrid modelling approach based on topo-edaphically constrained projections of climate-driven vegetation change potential, coupled with weather- and fuel-based simulations of future wildfires, and projections of large-scale industrial development activities, to better understand factors influencing decadal-scale upland vegetation change. I simulated scenarios of change in forest composition and structure over the next century, conservatively concluding that at least one-third of Alberta’s upland mixedwood and conifer forest is likely to be replaced by deciduous woodland and grassland by 2090, with a disproportionate loss of both young and old forest classes. During this timeframe, the rate of increase in fire probability diminished, suggesting a negative feedback process by which a warmer climate and more extensive near-term fires leads to an increase in deciduous forest that in turn, due to its relatively low flammability, leads to a long-term reduction in area burned.

Finally, boreal species’ projected range shifts could be impeded by the northwestern cordillera, which separates boreal Alaska from the rest of the North American boreal region, and appears to have historically prevented many species from expanding into climatically suitable habitat after the last glacial maximum (LGM). Using paleoclimate simulations for the past 20,000 years, I analyzed the relative importance of migratory and life-history characteristics vs. climatic factors on the distributions of North American boreal-breeding species. I then used this information to predict which species are most likely to shift their distributions from Canada into the Alaskan boreal region in the future. The high relative importance of climatic suitability within the northwestern cordilleran region suggests a capacity for several species to disperse into Alaska once climatic connectivity is achieved in the future, which is supported by recently recorded signs of breeding activity.

Integrating ecological and social approaches for promoting the conservation of carnivores in a human-dominated landscape of southern Chile

Darwin's fox spotted by a trail camera in Chile.

Darwin’s fox spotted by a trail camera in Chile.

This Friday, Wild49 lab member Dario Moreira will be defending his PhD thesis. His talk is open to the public and will be held in the University of Alberta Biological Sciences Building room CW313 at 9am.

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Kodkod cat detected by a trail camera in Chile.

Talk Summary: Mammalian carnivores inhabiting human-dominated landscapes often face reduced and more widely distributed in combination with greater exposure to humans and exotic species. I evaluated how habitat transformation and human activity shaped the spatio-temporal patterns of occupancy and prey selection of carnivores inhabiting a landscape dominated by exotic forest plantations in Southern Chile. Carnivore species responded to landscape attributes and the presence of domestic dogs. These effects were influenced by time of day as well as the spatial scale. For instance, the positive effect of native forest on occupancy probability was stronger during the night for the Darwin’s fox and cougar. Dogs negatively affected the occupancy probability of Darwin’s foxes, but this was independent of the time of day, compared to cougars, who were negative affected by dogs during day-time only. Vegetation structure derived from high-resolution LiDAR remote sensing systems improved the performance of occupancy models for mesocarnivores indicating that these species respond to fine-grained habitat heterogeneity. Prey selection of mesocarnivores differed between native forest and pine plantations and this was associated with changes in the abundance of prey species. The perceptions of carnivores by rural communities varied across species, with people being willing to adopt sustainable practices related to the husbandry of domestic animals, but they were unwilling to leash dogs or provide diurnal protection to poultry.

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Monito del Monte (Dromiciops gliroides) in Chile.

Influence of anthropogenic development on Burrowing Owl habitat selection and fitness

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Corey holding a burrowing owl, photo by Kent Russell.

Bayne lab member Corey Scobie is defending his thesis on Wednesday, June 3, 2015 at 9am at the University of Alberta in Biological Sciences Building CW313. Come check out his public seminar: “influence of anthropogenic development on Burrowing Owl habitat selection and fitness.”

Anthropogenic development may influence the choices animals make and their resulting fitness. I examined habitat selection of Burrowing Owls at several scales and their resulting breeding season fitness. First, I identified the types of landscapes features Burrowing Owls prefer to have around their nest and examined the relationship between these preferred features and fitness. They prefer to nest in landscapes with more annual crop and more road surfaces; features that had an unexpected positive influence on fledging rate. Second, I tracked adult male Burrowing Owls with GPS dataloggers and examined owl space-use during the day and night. During the day, Burrowing Owls spent more time near fences and posts, but avoided roads with high traffic speeds. At night, human infrastructure influenced where owls spent time more than artificial sound and light. However, owl selection of landscape features at night did not predict reproductive success. Instead, I found owls that spent more time near the nest burrow at night had the greatest nest survival and fledging rates. Burrowing Owls are a generalist species that is able to breed successfully in developed landscapes.

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Burrowing owl on a fence post, photo by Janet Ng.