By Mason Lee, Texas A&M WFSC '15
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| A Texas
Horned Lizard (Phrynosoma cornutum)
basks in the first rays of morning sunlight
What do a bobwhite quail and a Texas horned lizard have in
common? There doesn’t seem to be much of
a connection between the two. One has feathers where the other has scales. One
can fly when the other is resigned to an entirely terrestrial life. Despite
these differences, Rolling Plains Quail Research Ranch may have found the
answer to this odd question.
Rolling Plains Quail Research Ranch (RPQRR) boasts 4,700
acres of prime quail habitat. The focus of the ranch is developing and
understanding land management to increase populations of quail. In the process,
RPQRR has also created ideal habitat for a native reptilian that has been in
decline in recent years. The Texas horned lizard has seen its populations drop
by about 30% due to habitat destruction, the introduction of non-native fire
ants, and the application of insecticides (McIntyre 2003). Luckily for Texans, our state reptile has
found a safe haven at RPQRR. As it turns out, bobwhites and horned lizards have
similar habitat needs.
Texas horned lizards and bobwhites both need a mosaic of
different habitat types in order to thrive. Horned lizards require bare ground
in the mornings for thermoregulation and to forage their main food source, the
harvester ant (Burrow et al. 2001). Bobwhite quail also need ground with
minimal debris for nesting, as their newly-hatched chicks need to be able to
travel between sites (Oklahoma Department of Wildlife Conservation 2013). In
the afternoon, horned lizards utilize woody vegetation and leaf litter for
refuge from heat and cover from predators. They can find these sites in
bobwhite quail habitat, as bobwhites also use woody vegetation for escape cover
and nesting. For example, prickly pear is a common cover used by horned lizards
that also happens to be a choice nesting location for bobwhites (Burrow et al.
2001).
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northern bobwhite seeking cover in the Rolling Plains Ecoregion of Texas Mesquite is another woody plant that both bobwhites and horned lizards use. Horned lizards select mesquite as both an escape cover and a cover under which they forage for harvester ants (Eifler et al. 2012). Bobwhites frequently use this woody species for escape cover as well (TPWD 2005). Native grasslands also provide great benefit for both bobwhites and horned lizards. Insects are a favored food source of quail that can be found in great abundance in native grasslands. Harvester ants, the primary forage of horned lizards, also seem to favor these native grasslands as prime locations for their mounds (McIntyre 2003). |
One concern might be how horned lizards respond to common
land management practices for bobwhites, such as prescribed burning and
disking. It was found that these
practices actually provide many benefits to the horned lizards (Fair and Henke
1997). Horned lizards seemed to select burned plots more frequently than grazed
or disked plots for habitat, but they still favored disked plots over grazed
plots. These areas afford both bobwhites and horned lizards high percentages of
canopy cover to avoid predator detection and minimal amounts of ground litter
so that their movement is not impeded (Fair and Henke 1997). Moreover, it was
found that regardless of the land management treatment, the microhabitat
selection of the horned lizards did not change (Burrow et al 2001).
The Texas horned lizard, listed as threatened in Texas, is a
common find out at the ranch. In fact, the Dallas Zoo is utilizing the RPQRR to
study the life history of these lizards. They hope that by studying the habitat
preferences, diets, and activities of the horned lizards, they will be able to
better understand how to help bring back our native Texan reptiles. The
researchers have been doing mark- recapture studies for three field seasons and
have already experienced many unusual conditions that will give them a more
well-rounded view of horned lizard ecology. According to Bradley Lawrence, the reptile and amphibian supervisor of the Dallas Zoo, the researchers have
captured about 900 lizards and inserted a PIT (Passive Integrated Transponder) tag
in about 520 of the larger lizards. This allows them to relocate the lizards in
order to identify which habitat and microhabitats the horned lizards select. In
addition, the Dallas Zoo has taken some of the lizards into captivity to breed
them in the hopes of exchanging genes with other zoos and eventually
re-releasing the lizards into areas of suitable habitat in Texas. Although no
data from the research has yet been published, the long-term trends of this
healthy lizard population will shed some light on this declining species. For
more information on the Dallas Zoo’s work, visit the Texas Horned Lizard
Conservation website.
It appears that efforts to improve habitat for bobwhites
will in turn improve the habitat for horned lizards, and vice versa. Hopefully, the restoration and management of
the land for bobwhites will not only increase their and the horned lizard’s
habitat, but also that of the black-footed ferret, Attwater’s prairie chicken, and
many other endangered and threatened Texan species (TPWD 2005). The similar
habitat requirements of these diverse animals may be the link that helps them thrive
on managed lands such as the RPQRR.
Literature Cited
Burrow, Anna L., et al. 2001.
Microhabitat selection by Texas horned lizards in southern
Texas. The Journal of
Wildlife Management 65: 645-652.
Eifler, Douglas A., et al. 2012.
Habitat selection by foraging Texas horned lizards, Phyrnosoma cornutum. The
Southwestern Naturalist 57: 39-43.
Fair, W. Scott and Scott E.
Henke. 1997. Effects of habitat manipulations on Texas horned lizards and their prey. The
Journal of Wildlife Management 61: 1366-1370.
McIntyre, Nancy E. 2003. Effects
of conservation reserve program seeding regime on harvester ants (Pogonormyrmex), with implications for
the threatened Texas horned lizard (Phrynosoma cornutum). The Southwestern Naturalist
48: 274-277.
Oklahoma Department of Wildlife
Conservation. 2013. Bobwhite quail ecology. Oklahoma Quail Habitat Guide. May/June
2013; chapter 3:10.
Texas Parks and Wildlife
Department (TPWD). 2005. Where have all the quail gone? PWD RP W7000 1025.
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