After spending a couple weeks in New Mexico (and the lead up to the trip) these birds became a bit of an obsession. There are power point slides to demonstrate just the level I took this obsession that will remain secret until I die and are housed with my partner who will protect them with his life as well.
Being a comparative psychologist, it just made sense that I would dive into the literature and find out what was out there. I was surprised by how little there was.
Martin (1973) studied two locations of owls outside of Albuquerque (15 breeding pairs). It's a really nice overview if you haven't ever read a bird paper and don't know anything about owls, burrowing in particular.
Here's what I'm finding most interesting about these animals -- and I suspect a lot of it has to do with the fact that I study primates and sometimes canines. In these species, we see sexual dimorphism. The males are typically larger (in some cases much larger) than the females. We posit that this is because of mate defense. Sterck and colleagues (1997) post that given that resources are the limiting factor for female reproduction, females tend to map onto food patches. Given that females are the limiting factor for male reproduction, males tend to map onto females. Different sorts of social groups arise from this given the type of food, the distribution of the food, and how much of each (food and mates) can be guarded by one or more animals.
Martin (1973) found that the males were heavier that the females by a mean of 7.9 g. (These are little birds). However, strigiformes (aka owls) exhibit something called reversed sex dimorphism (RSD). In these birds, and in falconiformes, the female is larger than the male. Plumpton and Lutz (1994) found that female burrowing owls were smaller than males on all measures rectrix length (tail feathers, I think), wing chord (wing length for us lay folks), tarsometatarsus length (body length, I think). The females were, however, heavier than the males. The authors acknowledge that this was during nesting time and the female mass might be larger due to reproductive events (eggs, nesting).
So here's what I'm thinking about. What are the selection pressures that select for RSD in other owls? I need to also look this up and find some research on what that looks like. And then, what are the different selection pressures that do not select for RSD in burrowing owls? Plumpton and Lutz (1994) make an interesting argument at the end of their paper that the lack of RSD in burrowing owls might help to inform why we see RSD in raptors like falconiformes and strigiformes (are owls raptors?).
Next question is about burrowing owls hissing like rattlesnakes!!!
I include references in case you're interested in reading about burrowing owls!
Botelho, Eugene S., Patricia C. Arrowood, and D. M. Bird. “Nesting Success of Western Burrowing Owls in Natural and Human-Altered Environments.” Raptors in Human Landscapes. Academic Press, New York, 1996, 61–68.
Butts, K. O., and J. C. Lewis. “The Importance of Prairie Dog Towns to Burrowing Owls in Oklahoma.” In Proceedings of the Oklahoma Academy of Science, 62:46–52, 1982. http://digital.library.okstate.edu/oas/oas_pdf/v62/p46_52.pdf.
Catlin, D. H., D. K. Rosenberg, and K. L. Haley. “The Effects of Nesting Success and Mate Fidelity on Breeding Dispersal in Burrowing Owls.” Canadian Journal of Zoology 83, no. 12 (2005): 1574–80.
Conway, Courtney J., Victoria Garcia, Matthew D. Smith, and Katie Hughes. “Factors Affecting Detection of Burrowing Owl Nests during Standardized Surveys.” The Journal of Wildlife Management 72, no. 3 (2008): 688–96.
Conway, Courtney J., and John C. Simon. “Comparison of Detection Probability Associated with Burrowing Owl Survey Methods.” The Journal of Wildlife Management, 2003, 501–11.
Desmond, Martha J., and Julie A. Savidge. “Factors Influencing Burrowing Owl (Speotyto Cunicularia) Nest Densities and Numbers in Western Nebraska.” American Midland Naturalist, 1996, 143–48.
Haug, Elizabeth A., and Andrew B. Didiuk. “Use of Recorded Calls to Detect Burrowing Owls (Uso de Llamados Grabados Para Detectar La Presencia de Athene Cunicularia).” Journal of Field Ornithology, 1993, 188–94.
Haug, Elizabeth A., and Lynn W. Oliphant. “Movements, Activity Patterns, and Habitat Use of Burrowing Owls in Saskatchewan.” The Journal of Wildlife Management, 1990, 27–35.
Levey, Douglas J., R. Scot Duncan, and Carrie F. Levins. “Animal Behaviour: Use of Dung as a Tool by Burrowing Owls.” Nature 431, no. 7004 (2004): 39–39.
Machicote, Marcela, Lyn C. Branch, and Diego Villarreal. “Burrowing Owls and Burrowing Mammals: Are Ecosystem Engineers Interchangeable as Facilitators?” Oikos 106, no. 3 (2004): 527–35.
Martin, Dennis J. “Selected Aspects of Burrowing Owl Ecology and Behavior.” Condor, 1973, 446–56.
Owings, Donald H., Matthew P. Rowe, and Aaron S. Rundus. “The Rattling Sound of Rattlesnakes (Crotalus Viridis) as a Communicative Resource for Ground Squirrels (Spermophilus Beecheyi) and Burrowing Owls (Athene Cunicularia).” Journal of Comparative Psychology 116, no. 2 (2002): 197.
Restani, MARCO, L. R. Rau, and D. L. Flath. “Nesting Ecology of Burrowing Owls Occupying Black-Tailed Prairie Dog Towns in Southeastern Montana.” Journal of Raptor Research 35, no. 4 (2001): 296–303.
Rowe, Matthew P., Richard G. Coss, and Donald H. Owings. “Rattlesnake Rattles and Burrowing Owl Hisses: A Case of Acoustic Batesian Mimicry.” Ethology 72, no. 1 (1986): 53–71.
