Article 9:

(Case Study) Supplemental Cases for Case Study 11.3 Scat: Singing the Wildlife Conservation Blues

By Samuel K. Wasser and Kathleen Hunt, University of Washington, Seattle

There are many emerging applications of genetic and hormonal analyses based on scat. Here we describe two new areas we are working on at the Center for Conservation Biology at the University of Washington.

North Atlantic Right Whales: Opening the Black Box of Whale Biology

The North Atlantic Right Whale (NARW) (Eubalaena glacialis glacialis), is one of the most highly endangered whales in the world, and is the only one of the “great whales” that has never recovered after the cessation of whaling. Classified as Endangered on the IUCN Red List and as endangered under the U.S. Endangered Species Act, only about 300 individuals remain today (NOAA 2005). The NARW is currently suffering both from high mortality, primarily due to ship strikes and entanglement in fishing gear, and a mysteriously reduced reproductive rate decline that began in the 1990’s. The nature and cause of the reproductive decline remains unknown. It would be particularly helpful to know if the whales simply are not breeding, or if females are becoming pregnant but having miscarriages, or producing calves that then die for some reason.

The usual difficulties of studying large wild animals are brought to an extreme in right whales. They are nearly impossible to observe because they spend most of their time underwater. They are nearly impossible to tag or track because they immediately scrape off any attached tags by rolling on the ocean floor (S. Kraus, pers. comm.). They are impossible to capture or collect blood samples from. All in all, these whales are extraordinarily poorly understood—we lack even the most basic information about their biology (e.g., the timing of conceptive breeding) and we don’t even know where they are for most of the year. Most NARW simply vanish in the fall and reappear the following summer.

A small but dedicated team of researchers led by Dr. Scott Kraus has been studying this intriguing species intensively for 25 years, and as a result almost all individuals have been photo-identified and are of known age and known maternal lineage. These researchers formed the North Atlantic Right Whale Consortium to pool information and research efforts.

In the late 1990’s, Drs. Rosalind Rolland and Scott Kraus of the New England Aquarium and the North Atlantic Right Whale Consortium suspected that right whale feces, which smell awful, are bright orange, and float, could potentially open up the black box of right whale biology. Drs. Rolland and Kraus contacted our laboratory to see if we could perhaps measure any hormones in these whale feces. She then designed customized fine-mesh nets, used to scoop up the feces before they sank, and distributed the nets to all boats that might encounter right whales. We have since found that we can indeed measure whale fecal hormones, and that fecal estrogens, progestins, and androgens vary significantly with age (immature versus mature), sex, and reproductive condition of a whale. Mature animals of both sexes can be distinguished from immatures—the first known method of assessing reproductive maturity in baleen whales. Males can also be distinguished from females, by estrogen/androgen ratio. Lactating females have a distinct hormone profile of high fecal estrogens with normal fecal progesterone, and pregnant females are immediately obvious from their extraordinarily high progesterone levels (Rolland et al. in press).

We were also able to assess whether fecal glucocorticoids reflect chronic stress using a few rare samples from whales entangled in fishing gear. One severely entangled whale (#1102, “Churchill”) had extremely high fecal glucocorticoids levels, and died shortly afterward, despite intensive disentanglement efforts. Another whale (#2320, “Piper”) had a milder entanglement that had lasted over one year (she is still entangled as of this writing). She was in surprisingly good body condition, and had apparently habituated to the entanglement, having low fecal glucocorticoids. Though our sample sizes are tiny, these results suggest that fecal glucocorticoids may well be a good measure of chronic stress in this species (Hunt et al. 2003).

There was still one problem though. Despite the bright red coloration, distinctively horrible smell, and flotation of right whale scat, it was difficult to collect samples from the whales before the scat sank. So, we decided to see if scat detection dogs could improve sample acquisition from these whales. Two dogs previously trained to detect scat of terrestrial species were trained to ride on the bow of a boat. On board the boat, a dog handler observed and interpreted changes in dog body language and relayed them to the boat pilot, who assessed prevailing wind and current and redirected the boat accordingly. Gratifyingly, this novel scat detection method increased fecal sample collection rate by nearly eight-fold. Dogs were able to direct boats to samples that were initially a full nautical mile away (Rolland et al. 2005). This new collection method has dramatically increased acquisition of these extremely informative and valuable fecal samples from these highly endangered whales.

The results of these fecal hormone analyses have generated considerable excitement in the whale community because it has never before been possible to assess maturity, reproductive state, and stress level in any baleen whale. Clearly this technique will be of considerable use in assessing the cause of reproductive decline in this species.

Northern Spotted Owl

The Northern Spotted Owl (NSO) (Strix occidentalis caurina) is threatened throughout its range in British Columbia, Washington, Oregon and northern California. It is nearly extinct in British Columbia, and, if trends continue, will suffer a similar fate in Washington (Courtney et al. 2004). The owls appear to be doing better in Oregon and California due to the increased presence of mixed forest stands. Presumably the owls are able to generalize more on prey such as woodrats and deermice in these areas as opposed to specializing nearly exclusively on a diet of flying squirrels in the old growth forests of British Columbia and Washington. Likely problems facing the owls include habitat loss; reduced recolonization on state-owned land due to premature logging of previously occupied nest sites; invasion of barred owls from the eastern U.S., which are food and nest site competitors as well as predators of the NSO; lack of prey availability; and soon perhaps the spread of West Nile virus (Courtney et al. 2004).

We have incorporated our physiologically-based scat measures into a monitoring program in Washington (on the Yakima Indian Reservation) to assess the various disturbance impacts on these owls for eventual use as an adaptive management tool both in this site and throughout NSO’s range. We injected the closely related Barred Owl (Strix varia) and the more distantly related Great Horned Owl (Bubo virginianus) with radiolabelled cortisol, estradiol, testosterone and progesterone to assess: (1) how rapidly these hormones are excreted in feces and urine; (2) the relative suitability of fecal versus urine samples for hormone studies in the field; and (3) the best antibodies to use to measure these hormones (Wasser and Hunt in press). The Barred Owl was used as a surrogate for its threatened counterpart, the NSO. The Great Horned Owl was included as a more distantly related cross-check assuming that if results corresponded between the Barred and Great Horned Owls they would surely apply to the NSO. This was followed by studies on NSOs to assess whether the chosen antibodies were reliably measuring biological activity (Wasser et al. 2000). Fecal collections in the field were used to examine the impacts of roads and logging practices on these owls (Wasser et al. 1997), as well as effects of sex and reproductive stage on susceptibility to disturbance stress (Wasser and Hunt in press).

Repeated sampling of tagged owls on the Yakama Indian Reservation showed that stress levels were doubled in males whose home ranges were within 0.41 km of major roads or timber harvests compared to those further away. Male owls exposed to clear-cut timber harvests on private lands on the east slope of the Cascade Mountains also had significantly higher fecal stress hormone levels compared to those exposed to selective timber extraction on the Yakama Reservation (Wasser et al. 1997). Owls cross-sectionally sampled across Washington and Oregon by state and federal crews conducting owl surveys showed significant sex differences in fecal stress hormone concentrations as a function of breeding stage. Stress levels were highest in males and lowest in females during the nesting period. Concentrations progressively decreased in males and increased in females as reproduction progressed, peaking in females during the fledging period while lowest in males during that period. These results illustrate the potential utility of these hormone measures as an adaptive management monitoring tool in this at risk species. For example, the results suggest that restricting timber harvest at any given breeding stage will likely have different impacts on males versus females. Such information is vital to guiding future management actions. In addition, preliminary results suggest that owls with the highest fecal stress hormone measures in the Olympic National Park were those who abandoned their nests in response to Barred Owl invasion shortly after the study (Scott Grimmel, pers. comm.). Fecal stress hormone measures may thus prove useful in the future for illuminating impacts of invading Barred Owls on the threatened NSO. Our newest effort is undertaken by Lisa Hayward, a post-doctoral fellow in our Center, who is using hormone measures to examine impacts of off-highway vehicles on NSOs in California.

We are excited by what these techniques have to offer us in studying the effects of stress on wildlife populations, without causing the additional stress of capture and handling on endangered species.

Literature Cited

Courtney, S. P., J. A. Blakesley, R. E. Bigley, M. L. Cody, J. P. Dumbacher, R. C. Fleischer, A. B. Franklin, J. F. Franklin, R. J. Gutiérrez, J. M. Marzluff, and L. Sztukowski. 2004. Scientific evaluation of the status of the Northern Spotted Owl. Sustainable Ecosystems Institute, Portland, Oregon.

Hunt, K. E., R. M. Rolland, S. D. Kraus, and S. K. Wasser. 2003. Fecal glucocorticoid analysis as a potential tool for investigating physiological stress in North Atlantic right whales (Eubalaena glacialis). Integrative and Comparative Biology 43:1007–1007.

NOAA. 2005. Northern Right Whales (Eubalaena glacialis glacialis).
www.nmfs.noaa.gov/pr/species/mammals/cetaceans/

Rolland, R. M., K. E. Hunt, S. D. Kraus, and S. K. Wasser. 2005. Assessing reproductive status of right whales (Eubalaena glacialis) using fecal hormone metabolites. Gen. Comp. Endocr. 142:308–317.

Wasser, S. K. and K. E. Hunt. Noninvasive measures of reproductive function and disturbance in the Barred Owl, Great Horned Owl, and Northern Spotted Owl. Ann. NY Acad. Sci. In press.

Wasser, S. K., K. E. Hunt, J. L. Brown, K. Cooper, C. M. Crockett, U. Bechert, J. J. Millspaugh, S. Larson, and S. L. Montfort. 2000. A generalized fecal glucocorticoid assay for use in a diverse array of non-domestic mammalian and avian species. Gen. Comp. Endocr. 120:260–275.

Wasser, S. K., C. S. Houston, G. M. Koehler, G. G. Cadd, and S. R. Fain. 1997. Techniques for application of fecal DNA studies of Ursids. Mol. Ecol. 6:1091–1097.