A student climbs into a Ferruginous Hawk nest to retrieve nestlings to band with a color-coded and uniquely numbered leg band.
Photo by Janet Ng
-A view from above: A video of Ferruginous Hawk nestlings using a pole mounted camera.
Post and Video by Cameron Nordell
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.
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.
Justine Kummer and I spent a few days down south near Pincher Creek, AB, with Bayne-lab graduate student, Jesse Watson, to catch his study species, ferruginous hawks (FEHA). Hawk work is VERY different from deploying automated recording units (ARUs) in boreal Alberta, which I am quite familiar with for my own study focused on bioacoustics. I’ve heard the Raptor Ecology and Conservation Team (REACT) has spent so much time driving throughout southern Alberta and Saskatchewan searching for and monitoring FEHA nests that they could have actually traveled to the moon and back (and then some)… I now understand how this could be the case.
For the most part, FEHA work consists of driving all over the prairies monitoring various hawk nests. Along with watching these birds from afar, FEHA researchers also peep into the nests to count and monitor the chicks, something that Justine and I got to experience as well. Jesse’s project on FEHA deals with tracking the movements of this species during the breeding season. This season he was interested in attaching transmitters on individuals nesting on transmission towers in the western edge of the study area (Fort Macleod region).
In order to get location data for the FEHA, Jesse attaches solar-powered GPS transmitters to the back of the male FEHA he catches. Males are selectively chosen, as they will explore the entirety of the home range of each breeding pair of FEHA to search for food to bring home to his female partner and chicks. Additionally, the male is responsible for defending his territory. The female will move a bit throughout this area, but most of her time is spent in the nest with the young, making her a less ideal candidate to track.
On our third day of FEHA work, Justine and I got to experience the thrill of interacting with these birds. We managed to catch both the female and male of a breeding pair that were nesting on a transmission tower! It isn’t everyday that both of the adults get caught, so everybody was quite excited. We took measurements and weights from both birds and then released the female while Jesse worked quickly to stitch together the strands of the GPS transmitter backpack that was now sitting on the back of the male. Once the transmitter was secured, I got to release the male, and he headed straight back to his home on the transmission tower. It was an incredible experience, and I am so grateful to have had this opportunity to learn about the cool work going on in my own lab!
Now I am heading back to the boreal for more ARU deployments and to search for some broad-winged hawk (BWHA) nests for Jesse to trap at next. As an experiment, all of the boreal researchers should wear step-counters to see how close we’re getting to the moon with all of our walking!
Post by Natasha Annich
Jesse Watson is out catching Ferruginous Hawks for his research – he is studying the effects of industrial development on hawk movements. Today was a productive and exciting day – he caught a male and female Ferruginous hawk! It is rare to capture to both members of a breeding pair, so this is a particularly exciting catch. Both were banded, and the male was fitted with a GPS transmitter before being released. Check out Jesse’s research page for more information about his project.
It’s that time of year again when we expect wintering Ferruginous Hawks to begin moving northward as they return to their breeding grounds. Currently, the Raptor Ecology and Conservation Team (REACT) is tracking 13 hawks located in Colorado, Kansas, Texas, California, and Coahuila, Mexico on their wintering grounds. See below for a map displaying the southward migration from this fall and the wintering locations where the hawks are currently located. Check back soon for spring migration updates!
Written by Jesse Watson
Field assistants needed for ferruginous hawk research project.
We are looking to hire 2-3 field assistants for an ongoing collaborative University of Alberta & Environment Canada study on the relationship between Ferruginous Hawks and industrial development in Alberta and Saskatchewan. Tasks include nest searching and monitoring, behavioural observation, capture, banding, automatic recording unit (ARU) setup. Additional duties will include landowner communication, identifying habitat characteristics, and other related tasks.
Applicants must have excellent note-taking skills (detailed and accurate), valid class 5 driver’s license with clean record, be capable of driving long distances, and cannot be afraid of heights, bugs, or heat. Top applicants will possess: strong communication skills, raptor (and overall avian ID experience), some bird (raptor) handling experience, strong climbing ability, and aptitude for technology based work. Additional assets include driving 4WD trucks, vegetation identification experience, knowledge of Alberta’s Species At Risk, and navigational skills.
Pay rate for field assistants ranges between $2300 – $2800 CDN/month depending on experience. Housing and food are included while in the field. Work period typically consists of a 10 days on / 4 days off rotation; this is flexible, but overall work period amounts to 22 days/month. Work terms starting in both early April continuing through July 31 with the possibility of extension. Field work is primarily in southern Alberta, with some travel to southern Saskatchewan.
Apply early before the positions are filled! Applications will be accepted until March 6th, 2015. Please send a resume, cover letter, three references, and available start date to: Janet Ng (Janet.NgATualberta.ca).
While attaching GPS transmitters to Ferruginous hawks in the summer of 2014, Jesse Watson and Cam Nordell encountered a number of composed, charismatic male Ferruginous Hawks, like those pictured below. Typically, a male Ferruginous Hawk eye color will range from a light brown to a fairly dark brown. Interestingly, in many raptor species, a keen observer will often be able to detect a change in eye color with age.
During the attachment of the last transmitter of the summer Cam and Jesse encountered a particularly spectacular eye color in one individual. Below you can see the fantastic golden eye color of this particular male.
If you look really closely you can actually see Cam and Jesse in the reflection of his retina. It takes a brave researcher to meet the steely gaze of one of the Canadian Grasslands top predators, but it was a fitting end to the 2014 Ferruginous Hawk transmitter attachment season.
Written by Cameron Nordell