Book Review: Living with coyotes: managing predators humanely using food aversion conditioning

I was initially worried after receiving a phone call from a predator advocate who told me that I must see the new book that explained how conditioned food avoidance (CFA) could be used to solve the problem of coyote predation. “New?” I thought, recalling the acrimonious debates over CFA in the journal Appetite and elsewhere in the 1980s. On reading the book, however, I was pleasantly surprised to find that Living with coyotes by Stuart Ellins is not an extension of the ongoing diatribes that started so long ago. Instead, the book acknowledges that many of the previous heated debates could be reduced to personal differences in the philosophy of science

Are Vultures Birds, and Do Snakes Have Venom, because of Macro- and Microscavenger Conflict?

I outline models that describe vertebrate and microbial competition for carrion resources and help explain the resultant morphologies observed in extant vertebrate scavengers. Odors from microbial decomposition signal the presence of a carcass to vertebrate scavengers. Therefore, microbes must consume carcasses rapidly or evolve toxic defenses to protect themselves and their resource from their vertebrate competitors. Similarly, macroscavengers must evolve traits that allow rapid detection of carcasses or develop chemical defenses against microbial toxins. My modeling suggests that the most efficient macroscavenger adaptations increase the probability of carcass detection, which explains why highly vagile species, such as vultures, are the most obligate of vertebrate scavengers. Empirical data from vultures and from a scavenging snake species suggest that evolutionary pressures favor detection maximizers relative to toxification minimizers in competitive interactions for carcasses. However, detoxification mechanisms allow safe consumption of carrion and may have influenced the development of the complex digestive enzymes and delivery systems now seen in minimally vagile scavenging snakes

Book Review: Living with coyotes: managing predators humanely using food aversion conditioning

I was initially worried after receiving a phone call from a predator advocate who told me that I must see the new book that explained how conditioned food avoidance (CFA) could be used to solve the problem of coyote predation. “New?” I thought, recalling the acrimonious debates over CFA in the journal Appetite and elsewhere in the 1980s. On reading the book, however, I was pleasantly surprised to find that Living with coyotes by Stuart Ellins is not an extension of the ongoing diatribes that started so long ago. Instead, the book acknowledges that many of the previous heated debates could be reduced to personal differences in the philosophy of science

Carrion Seeking in Brown Tree Snakes: Importance of Olfactory and Visual Cues

We performed field experiments to examine brown tree snake (Boiga irregularis) attraction to carrion. These snakes were attracted to carrion and entered traps baited with dead mice as readily as traps baited with live mice. Using the cues arising from both live and dead prey, we examined the relative importance of visual and chemical cues to brown tree snakes. With carrion lures, chemical cues alone were sufficient for attracting and capturing snakes, but with live prey lures visual cues were required to attract and capture brown tree snakes. Our study presents the first experimental field evidence showing carrion to be attractive to an ophidian predator and suggests that the relative importance of chemical and visual sensory stimuli to brown tree snakes is context-specific

Mechanical Mouse Lure for Brown Treesnakes

The importance of prey movement for stimulating feeding behavior of Brown Treesnakes was tested by using a mechanical mouse model in combination with and without prey odor. Prey movement was found to be important in stimulating brown treesnake feeding behavior. Prey movement combined with prey odor was not significantly different than prey movement alone. In the development of simple artificial lures based on the stimulus of live mice, visual lures lacking movement are likely to be ineffective. Lures that combine a visual moving stimulus with prey odor are likely to be the most effective artificial lure for trapping brown treesnakes

Mechanical Mouse Lure for Brown Treesnakes

The importance of prey movement for stimulating feeding behavior of Brown Treesnakes was tested by using a mechanical mouse model in combination with and without prey odor. Prey movement was found to be important in stimulating brown treesnake feeding behavior. Prey movement combined with prey odor was not significantly different than prey movement alone. In the development of simple artificial lures based on the stimulus of live mice, visual lures lacking movement are likely to be ineffective. Lures that combine a visual moving stimulus with prey odor are likely to be the most effective artificial lure for trapping brown treesnakes

The effect of enclosure type on the behavior and heart rate of captive coyotes

The potential for captivity to elicit changes in animal behavior and physiology is well known. Recent research on captive populations has examined the effect of feeding protocols, enclosure types, and enrichment programs on indices of stress and displays of species-typical behaviors. We investigated the impact of enclosure type upon captive coyotes (Canis latrans) by examining differences in coyote behavior and heart rate, among 3.3m2 kennels (K), 65.5m2 small pens (S), and 1000m2 large pens (L). Time budgets and repertoire of species-specific behaviors were compared among each enclosure type and to a sample of wild (W) coyotes. Baseline heart rates and heart rate (HR) responses to food delivery and fecal collection (measured as mean heart rate and latency of heart rate to return to baseline) were also compared among treatments. We found that behavioral budgeting, but not repertoire, differed significantly among enclosure types. Relative to small and large pen enclosures, coyotes maintained in kennels exhibited the greatest amount of stereotypic behavior (P \u3c 0.0001). Coyotes kept in large pens were most similar to wild coyotes in the percentage of time they spent performing exploratory (K: 2.7%; S: 4.9%; L: 8.5%; W: 12.0%) and stand and scan (K: 8.0%; S: 16.4%; L: 22.0%; W: 22.3%) behaviors. Heart rate analysis showed that baseline heart rates and heart rate responses to food delivery did not differ significantly among enclosure types. Mean heart rate responses to fecal collection were significantly higher for kennel coyotes than for those maintained in large pens (P = 0.04). Similarly, latency to return to baseline was significantly higher in kennels than in small and large pens (P = 0.001). These results suggest that enclosure type does influence coyote behavior and heart rate responses to some human activities

Efficacy, effort, and cost comparisons of trapping and acetaminophen-baiting for control of brown treesnakes on Guam

Brown treesnakes (Boiga irregularis) are an invasive species to the island of Guam. Because they have extirpated the native forest avifauna on Guam and are a threat to other Pacific islands, the development of efficient and cost-effective methods to control them is desired. We compared the efficacy, cost, and effort required to remove brown treesnakes on 6-ha plots in forest scrub on Guam, using 2 methods: trapping and poison baiting. Toxic baits consisted of dead neonatal mice adulterated with 80-mg acetaminophen. To assess efficacy, we used mark-recapture methods to estimate snake abundance on plots 12 days before and 12 days after treatment. We also monitored bait-take or trap success for 20 days during treatment. From 6,304 trap-nights, we recorded 801 captures of 504 snakes on 6, 6-ha plots during a 51-day period. Snake populations on plots ranged from 41 to 107 prior to treatment. Using trapping to gauge survival of marked snakes, the 2 methods (trapping and baiting) had similar efficacies (0.05 to 0.1). Based on trapping, post-treatment population estimates ranged from 26 to 40, yielding reductions from estimated pre-treatment populations of 7 to 68% for both types of snake-removal treatments. Using post-treatment bait-take of unadulterated mice as an index of efficacy, poisoned baiting was twice as effective as trapping in diminishing snake activity. Trapped plots had post-treatment bait-take rates similar to reference plots (75%), whereas poison-baited plots had bait-take rates of 38%, suggesting that some snakes cannot be trapped and that baiting affects a wider range of the snake population. Because of the potential for baiting to impact more snakes, this method was about 1.67 times more cost effective than trapping. If baiting were to occur via aerial drop rather than via bait stations, the economic incentive for using baiting as a control strategy would be even greater. These observations will prove useful for managers making decisions about appropriate methods for control of brown treesnake populations

Ontogenetic relationships between cranium and mandible in coyotes and hyenas

Developing animals must resolve the conflicting demands of survival and growth, ensuring that they can function as infants or juveniles while developing toward their adult form. In the case of the mammalian skull, the cranium and mandible must maintain functional integrity to meet the feeding needs of a juvenile even as the relationship between parts must change to meet the demands imposed on adults. We examine growth and development of the cranium and mandible, using a unique ontogenetic series of known-age coyotes ( Canis latrans ), analyzing ontogenetic changes in the shapes of each part, and the relationship between them, relative to key life-history events. Both cranial and mandibular development conform to general mammalian patterns, but each also exhibits temporally and spatially localized maturational transformations, yielding a complex relationship between growth and development of each part as well as complex patterns of synchronous growth and asynchronous development between parts. One major difference between cranium and mandible is that the cranium changes dramatically in both size and shape over ontogeny, whereas the mandible undergoes only modest shape change. Cranium and mandible are synchronous in growth, reaching adult size at the same life-history stage; growth and development are synchronous for the cranium but not for the mandible. This synchrony of growth between cranium and mandible, and asynchrony of mandibular development, is also characteristic of a highly specialized carnivore, the spotted hyena ( Crocuta crocuta ), but coyotes have a much less protracted development, being handicapped relative to adults for a much shorter time. Morphological development does not predict life-history events in these two carnivores, which is contrary to what has been reported for two rodent species. The changes seen in skull shape in successive life-history stages suggest that adult functional demands cannot be satisfied by the morphology characterizing earlier life-history stages. J. Morphol. 2011. © 2011 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/84382/1/10934_ftp.pd