Monday, October 20, 2014Register
 Species Spotlight

[Photo: Ashok Kosla, National Audobon Society]
[Photo: Ashok Kosla, National Audobon Society]

Northern Bobwhite
Colinus virginianus

Description: The Northern Bobwhite is a small, rotund bird of the family Odontophoridae (New World Quail) with rounded wings and a square tail. Bobwhites typically weigh 5-6 ounces (140-170 g) and are 8-10 in (20-25 cm) long with a wingspan of 3.6-4.8 in (9-12 cm). Bobwhites are sexually dimorphic with males displaying much more vibrant coloration than females or juveniles. In general, bobwhite quails are reddish brown in color with white, brown, gray and black mixed in throughout the body. Both males and females have a black stripe that extends from the beak to the base of the head; however, males have a white stripe above and below the eye whereas females have buff colored striping.

Life History: Northern Bobwhites usually breed once a year although can breed up to three times a year from February to October. Males and females reach sexual maturity at one year of age and females lay up to 13 eggs per breeding season. The eggs require 23 day to hatch and after 2 weeks the fledglings leave the nest. Northern Bobwhite feed on grass seeds during the fall, acorns throughout winter, insects and leafy vegetation in the springs, and insects and fruits and berries during the summer. The Norther Bobwhite has high mortality rates with 80 percent living of the population living less that one year.

Habitat: Bobwhite quail habitat consists of grassland, the edges of agricultural fields, and open wood or scrub forest habitats. Bobwhites do well in recently disturbed (early successional) habitats, but they do require a range of invertebrates, seeds and herbaceous plants for food and a diversity of ground cover. Optimal habitat for bobwhite includes diverse bunchgrass communities with patchy bare ground between and prominent canopy cover to protect from the elements and predators. Northern Bobwhites build ground nests consisting of dead grasses.

Distribution: Colinus virginianus can be found from southeastern Ontario in Canada to Central America with higher densities in the central and eastern US.

Status: The Northern Bobwhite has been declining at a rate of 3 percent over the last 50 years due to habitat loss from urbanization, and changes in farming and forestry techniques. However, the bobwhite continues to remain abundant throughout its range due to its ability to utilize a range of habitats. The Northern Bobwhite is an important game species regionally and nationally, and land management using prescribed burning and other brush management techniques is quite effective at managing healthy bobwhite populations.

Resources:

South Carolina DNR - Northern bobwhite

Animal Diversity Web

Texas Tech University, Bobwhite Quail Profile


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 Tamaulipas-Texas Semi-Arid Prairies

 Tamaulipas-Texas Semi-arid Plain Level 4 Ecoregion Map [Figure: Houston Advanced Research Center]Tamaulipas-Texas Semi-arid Plain Level 4 Ecoregion Map [Figure: Houston Advanced Research Center]

The Tamaulipas-Texas Semi-Arid Plain or brush country is a vast dissected plain of thorny brush, in what used to be a predominantly grassland, savanna habitat. This ecoregion lies between the Chihuahuan Desert to the west and the coastal grasslands to the east and is comprised of four distinct subregions: The Northern Nueces Alluvial Plains, Semi-arid Edwards Bajada, Texas-Tamaulipan Thornscrub, and the Rio Grande Floodplain and Terraces.

The topography of the Tamualipas-Texas Semi-Arid Plains consists of irregular to gently rolling plains with deep, acidic, fine to coarsely textured alluvial soils that are well-drained and low in moisture. The elevation ranges from 80-1000 feet (25-300 m). The climate in this region is semi-arid, receiving only 17-30 inches of rain per year (42-75 cm), mostly during May and June. Severe drought is common in this ecoregion. Temperatures average 70-72 F (21-22 C), with a growing season of 260-310 days.

The vegetation in all four subregions is comprised of mostly thorn woodland and thorn shrubland.  The vegetation type is classified as mesquite-acacia-savanna and ceniza shrub which includes species such as honey mesquite, cactus, blackbrush, Texas persimmon, guajillo, lime pricklyash, and others.  The grasses are composed of mostly short to mid-length grasses such as little bluestem, sideoats grama, lovegrass tridens, cane bluestem, silver bluestem, and bristlegrass.  In wetter areas, along the Rio Grande, species such as black willow, black mimosa, common and giant reed, cattails, bulrushes and sedges can be found.  Some examples of wildlife common to the Tamaulipas-Texas Semi-Arid Plain are: coyote, ringtail, hog-nosed skunk, Mexican ground squirrel, southern plains woodrat, ghost-faced bat, green kingfisher, elf owl, long-billed thrasher, Mexican burrowing toad, Rio Grande leopard frog, giant toad, banded gecko, mesquite lizard, black-striped snake, and the speckled racer.

The major land use in the region is rangeland, with 90% of the land used for grazing cattle.  Croplands occur in the wetter Northern Nueces Alluvial Plains ecoregion as well as in the Rio Grande floodplain.  The crops grown here are corn, cotton, sorghum, small grains and vegetables.  The major human impacts on this ecoregion are from cattle grazing, water extraction, and fire suppression. These stressors have lead to the widespread dominance of drought tolerant thorny, brush species and a decrease of native grassland habitats.


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 Invasive Spotlight

[Photo: April Noble, Antweb.org, Bugwood.org]
[Photo: April Noble, Antweb.org, Bugwood.org]

Red Imported Fire Ant
Solenopsis invicta

Description: The red imported fire ant (RIFA) is a small, aggressive ant with a reddish-brown head and thorax and a darker colored abdomen or gaster. The thorax and abdomen are divided by a two-segment waist called the pedicel and post-petiole. These ants can be distinguished by their 10-segmented antenna terminating in a two-segmented club and the stinger at the tip of the gaster. RIFA ants range from 2-6 mm in length with body size dependent upon position in colony (e.g. minor worker, major worker, queen).

Life History: The life cycle of the red imported fire ant workers is 30-180 days depending on the size of the worker. The smallest worker is the minor worker, which lives 30-60 days, then the media worker (60-90 days) and the major worker (90-180 days). The queen can live from 2-6 years. RIFAs mate via a mating flight, which acts as the natural dispersal agent for a new colony. Once established in a nest and with enough food supply, a queen can produce up to 1500 eggs per day, with a typical colony consisting of 80,000 ants. Worker ants feed on dead animals such as insects, earthworms, and small vertebrates and bring back food for larvae. The larvae digest the food, which, in turn, is consumed by the workers and queen.

Habitat: RIFAs prefer hot arid regions, although they can survive in climate-controlled buildings in colder climates. These ants prefer to colonize in open areas such as agricultural and forest edge habitats, and tend to prefer recently disturbed areas. RIFA mounds are usually less than 46 cm in diameter with a honeycombed structure; although mounds are not always visible.

Distribution: Solenopsis invicta is native to South America, although it has become established in the US since it first arrived in either Mobile, AL or Pensacola, FL between 1933 and 1945. RIFAs currently inhabit almost all states from Maryland south to Florida and west to southern California.

Status: Red imported fire ants are aggressive invaders which are able to breed quickly and spread rapidly. The ability of these ants to bite and sting makes them excellent predators, allowing them to outcompete native ants and other invasive ants. RIFAs have been shown to severely harm local populations of ground nesting birds and mammals and may also kill frogs and lizards. There are additional costs of the RIFA associated with agriculture and public health.

Resources:

Global Invasive Species Database

U. of Florida Entomology - Fire Ant


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 Endangered Spotlight

[Photo: Texas Parks and Wildlife]
[Photo: Texas Parks and Wildlife]

Ocelot
Leopardus pardalis

Description: The ocelot is a medium-sized cat weighing 15-20 lbs (6.8-9 kg) and 30-41 inches (75-103 cm) long with a an intricate spotted and striped coat. The coat is variable colors with the upper body a grayish color with dark brown or black spots and splotches of various shapes. The underbelly is white with black spots and the tail is encircled with black rings or bars.

Life History: Ocelots occupy a home range of approximately 2-4 square miles (0.8-1.6 ha), with females occupying a smaller range than males. Ocelots traverse the home range mostly at night, stalking prey such as rabbits, small rodents and birds. Females return to the den during daytime, which consists of a depression in thick brush or grass. Females give birth from late spring through December and have litters of 1-2 kittens, on average. Kittens remain with the mother for about one year.

Habitat: Typical habitat of the ocelot consists of mixed brush species and trees found near the Rio Grande. Optimal habitat for the ocelot contains 95 percent canopy cover of shrubs, with 100 acres of isolated brush habitat. Smaller brush acreages must be connected to larger areas by habitat corridors in order to be used by the ocelot.

Distribution: Historically the ocelot occurred in vast areas in Texas including Central and Southern Texas and the Texas coastal plain.Leopardus pardalis is now restricted to 13 counties in Southern Texas: Cameron, Duval, Hidalgo, Jim Wells, Kenedy, Kleberg, Live Oak, McMullen, Nueces, San Patricio, Starr, Willacy and Zapata.

Status: The ocelot is a state and federally listed endangered species (1972). Due to habitat conversion into agricultural and urban development, the ocelot population has been steadily declining for the past 60 years and currently only supports approximately 80-120 individuals. According to TPWD only 1 percent of the current ocelot distribution area supports optimal ocelot habitat. Vehicle mortality has become an increasing problem for ocelots in southern Texas and has been attributed with 50 percent of ocelot mortality. Conservation of ocelot habitat and construction of habitat corridors are currently underway in the area.

Resources:

TX Parks & Wildlife - Ocelot

US Fish and Wildlife - Listed Cats


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