Whitehead, Hal

Permanent URI for this collectionhttps://hdl.handle.net/10222/22325

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Open Access
Cetaceans have complex brains for complex cognition
(2007-05) Marino, Lori; Connor, Richard C.; Fordyce, R. Ewan; Herman, Louis M.; Hof, Patrick R.; Lefebvre, Louis; Lusseau, David; McCowan, Brenda; Nimchinsky, Esther A.; Pack, Adam A.; Rendell, Luke; Reidenberg, Joy S.; Reiss, Diana; Uhen, Mark D.; Van der Gucht, Estel; Whitehead, Hal
No abstract available.
Open Access
Behavioral reactions of northern bottlenose whales (Hyperoodon ampullatus) to biopsy darting and tag attachment procedures
(2001-04) Hooker, SK; Baird, RW; Al-Omari, S.; Gowans, S.; Whitehead, Hal
The effects of invasive or intrusive research techniques need to be thoroughly documented in order to satisfy appropriate standards of animal care. How cetaceans react to either biopsy darting ol tag attachment procedures has been studied for several species, and considerable interspecific variability in responses has been demonstrated: however; few studies have compared reactions to both techniques. In the family Ziphiidae (the beaked whales) nothing has been previously reported on responses to either technique. We examined and compared the reactions of northern bottlenose whales (Hyperoodon ampullatus) to biopsy darting and tagging. Reactions to both these procedures were generally low-level and short-lived; stronger responses were given to hits than to misses. There was no statistical difference in observed response to tag versus biopsy hits. The prior behavioral state of the whales appealed to influence the magnitude of reaction to both hits and misses and thus may be an important Factor to consider in such impact assessment. Whales lying still at the surface showed stronger reactions than traveling or milling animals. Sea state appeared to affect whether there was a reaction to misses, Whales were more likely to respond to a miss in calm sea conditions. No avoidance of the research vessel was observed following a tag or biopsy attempt, and in moat cases whales approached the research vessel again within several minutes.
Open Access
Computer-Assisted Photo-Identification of Narwhals
(2011-09) Auger-Methe, Marie; Marcoux, Marianne; Whitehead, Hal
Although the narwhal (Monodon monoceros) is economically and culturally important to northern residents, sound management of this species is impaired by large gaps in knowledge. Research on this species has been limited partly by the cost of the methods used, and partly because some of these methods are invasive and therefore condemned by Inuit communities. Photo-identification, a non-invasive, inexpensive, and easy-to-use method recently developed for narwhals, uses photographs of natural marks to identify individuals. Its main drawback is the extended time required to process photographs. We developed a computer program to accelerate the identification process and thus mitigate the main drawback of photo-identification. This program uses the locations of notches on the dorsal ridge to compare a new image to each individual in a catalogue and lists those individuals in decreasing order of similarity. We tested consistency in user assignment of dorsal ridge features and the accuracy of the program by comparing sets of known individuals. While assignment errors were common, the program ranked the true match within the first 10% of the catalogue 78% of the time. The program accelerates the matching process by 1.2 to 4.1 times for catalogues ranging in size from 40 to 500 individuals, and the degree of acceleration increases with the size of the catalogue. This program could also be applied to the beluga whale (Delphinapterus leucas), another important northern species.
Open Access
Inferring Animal Densities from Tracking Data Using Markov Chains
(2013-04) Whitehead, Hal; Jonsen, Ian D.
The distributions and relative densities of species are keys to ecology. Large amounts of tracking data are being collected on a wide variety of animal species using several methods, especially electronic tags that record location. These tracking data are effectively used for many purposes, but generally provide biased measures of distribution, because the starts of the tracks are not randomly distributed among the locations used by the animals. We introduce a simple Markov-chain method that produces unbiased measures of relative density from tracking data. The density estimates can be over a geographical grid, and/or relative to environmental measures. The method assumes that the tracked animals are a random subset of the population in respect to how they move through the habitat cells, and that the movements of the animals among the habitat cells form a time-homogenous Markov chain. We illustrate the method using simulated data as well as real data on the movements of sperm whales. The simulations illustrate the bias introduced when the initial tracking locations are not randomly distributed, as well as the lack of bias when the Markov method is used. We believe that this method will be important in giving unbiased estimates of density from the growing corpus of animal tracking data.
Open Access
Analysis of animal movement using opportunistic individual identifications: Application to sperm whales
(2001-05) Whitehead, Hal
Data sets in which animals are identified individually in different places and times may contain considerable information on movements. However, if the probability that an animal is reidentified depends on its movement pattern, then standard methods of analyzing movement are not applicable. I show that modifications of maximum likelihood methods, in which the identifications themselves establish the spatial and temporal distribution of effort, can be used to derive movement parameters in three situations: (1) Identifications in one location allow calculation of the "lagged identification rate" (the probability of reidentification after various time lags) as well as estimation of residence times inside, and outside, the study area. (2) When more than one study area is sampled, it is possible to derive lagged identification rates between them and to estimate movement rates between areas and other population parameters. (3) Movements through continuous space can be described by diffusion rates (rates of population spread), and plots of squared displacement against time lag. To simplify computation, and to permit the analysis of large data sets, summed nonindependent log-likelihoods can be maximized in place of the true log-likelihood to obtain approximately unbiased parameter estimates, and binomial, multinomial, or hypergeometric models can be approximated by the Poisson distribution. The first and third of the techniques were verified using simulated data, and all were applied to a 13-yr data set of identifications of sperm whales in the South Pacific Ocean. Residence times in waters close to the Galapagos Islands were of the order of 8 d, but during the study period there was a substantial net movement out of the Galapagos region and into waters of the coastal eastern tropical Pacific. Diffusion rates of sperm whales were similar to 700 km(2)/d over time scales from 1 to 100 d but decreased considerably over time scales of years, indicating displacements of similar to 50 km/d within home ranges spanning similar to 1000 km. Although giving relatively imprecise estimates of movement parameters compared to more standard methods, the techniques considered here should be particularly useful when examining animal movements over long time scales.

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