It is tough being a quail. From egg to adult you are constantly tops on the dinner menu. But what do we really know about the predators of quail? Based on covert photography at nest sites, we tend to assume that raccoons, coyotes, bobcats, skunks and a host of other small predators spend much of their time on search and destroy missions against hapless quail. Yet predator removal programs consistently fail to create an abundance of quail. Something is amiss in our perception of the effect of predation on quail populations?
At RPQRR, we have an abundance of coyotes, a modest population of raccoons, but skunks are uncommon, and none of us has ever spotted an opossum, nor its tracks. Dr. Rollins hypothesizes that the coyotes suppress smaller mesocarnivores, either directly (i.e., preying on them) or indirectly (i.e., by restricting them to certain areas [e.g., riparian areas]). So how do coyotes and raccoons use the RPQRR's landscape, especially during the nesting season for quail?
Recent technological improvements have allowed us to enter the nocturnal world of mammalian predators. Last May we captured 4 coyotes and 8 raccoons, fitted them with collars containing GPS units and then set them free again. The GPS units logged the animal's precise location every 5 minutes from dusk to dawn for 5 weeks, then the collars released automatically. We retrieved them and downloaded the information which allowed us to unravel the mystery of the nocturnal movements of these predators.
The wily coyotes virtually never left the safety of RPQRR (coyotes are not controlled at RPQRR). They showed a strong preference for hunting in the grasslands and avoided the densely wooded creek beds. Each animal ranged over a territory of about 1,000 acres. Walking about 6 miles every night, in a month's time they obtained complete coverage of their territory. We know that dense stands of prickly pear within the grassland deter hunting dogs, but coyotes are made of sterner stuff than Dr. Rollins' bird dogs and they were undeterred by dense cactus. Even so, at night coyotes took advantage of the ranch roads for easy travelling, as confirmed by their numerous scat and tracks. RPQRR has quail feeders on some of these roads, but these did not appear to be of much interest to the coyotes.
Small predators have bigger predators of their own, so raccoons must be wary of coyotes. In fact one collared raccoon was found dead near a quail feeder on the day before his collar was to release, and it looked like he may have fallen prey to a coyote.
Female raccoons were strictly limited to the riparian areas with dense undercover and tall trees. Since quail do not inhabit such areas these female raccoons are presumed innocent of the crime of raiding quail nests. Whether they would venture into the grassland if coyotes were absent remains to be seen.
Male raccoons were much more adventurous. While females stayed within home ranges of only 120 acres, male raccoons used areas as large as those of coyotes and travelled about 4 miles each night. They used the wooded creek beds to range far beyond the boundaries of RPQRR.
Male raccoons often ventured beyond the protection of the wooded areas into the grasslands and onto the rocky hillsides where they dozed the day away under tangled boulders. Unlike the long-legged coyotes, raccoons strongly avoided entering the most cactus-infested grasslands. So while cactus may not afford quail much protection from coyotes it is apparently effective against raccoons.
When traversing cactus-laden grasslands, raccoons traveled along the ranch roads. The roads chosen were those on which feeding stations were set up for quail. At each feeder the raccoons lingered, obviously enjoying the easy meal of protein pellets and milo provided for the quail. This opens the question as to who is the main beneficiary of the supplemental food, the quail or their enemy? Could the provision of food be luring raccoons into quail nesting habitat or could it be decoying them from raiding nests by providing alternative food? Ongoing camera surveillance of feeders confirms that raccoons are frequent visitors.
GPS collars can only tell us where the predator went, not whether it found or missed a quail or its nest, but this study suggests that the effects of coyotes and raccoons on quail are not additive. Presumably, the presence of coyotes keeps at least the female half of the raccoon population in the dense cover away from prime quail nesting habitat. An analysis of coyote scat will reveal whether quail figure highly in the diet of coyotes. If not, then it may be worthwhile not to remove coyotes from land devoted to raising quail.
Dense cactus in the grassland, like predators, is often targeted for removal, yet it too helps protect quail by limiting access to nesting areas by raccoons. As noted in the January issue of e-Quail, cactus can be useful. Nest survival is improved by its prickly defenses against nocturnal prowlers. So tolerating both coyotes and cactus may keep the pesky raccoons at bay, giving the quail a better chance to produce the next generation.
(Dr. Cooper is an Associate Professor with AgriLIFE Research working out of the Uvalde office; she has become an integral part of our research effort at RPQRR.)