By Bart Ballard, Ph.D.
The Texas coast is a premier waterfowl hunting area that annually provides migration and wintering habitat for millions of ducks and geese. Its mild winter climate and diversity of wetland habitat attract a variety of waterfowl, especially northern pintails. During the 1970s, when continental pintail populations were last at high levels, more than 1 million of these birds wintered along the Texas coast. Pintails use a variety of habitats in this region including coastal ponds and open bays dominated by sea grasses, but the birds have an especially strong preference for flooded rice fields.
Unfortunately, a sharp decline in rice production in recent decades has greatly reduced wintering habitat for pintails and other waterfowl along the Texas coast. The decline in rice acreage has been especially severe in the Mid-Coast region west and south of Houston, an area that supports some of the largest concentrations of wintering pintails in the Central Flyway.
Ducks Unlimited and the Gulf Coast Joint Venture recently conducted habitat evaluation work investigating the impact declining rice production has had on wintering waterfowl in this region. The findings of this research indicate the Mid-Coast region currently has insufficient foraging habitat to support wintering populations of pintails and other waterfowl. In fact, this research suggests an additional 82,000 acres of foraging habitat must be restored to meet the birds' needs. Waterfowl spend much of their time feeding and resting during winter, and the birds need an abundance of high-quality foraging habitat to survive at acceptable rates over winter and to allow them to return north in good breeding condition.
DU and its joint venture partners are especially concerned about how declines in rice agriculture might affect wintering pintails along the Texas coast. During the last several years, DU has worked with the Caesar Kleberg Wildlife Research Institute at Texas A&M University–Kingsville to study the winter ecology of pintails in the region. These efforts have examined pintail over-winter survival, habitat use, local and regional movements, and body condition to assess potential effects of declining habitat on the birds.
The researchers were surprised to learn that female pintails had alarmingly low winter survival in the Mid-Coast region of Texas. Low over-winter survival is relatively uncommon in pintails and other waterfowl on other major wintering areas. Consequently, this research provided evidence that all may not be well for pintail populations that depend on this continentally significant wintering area.
Research has also confirmed that wintering pintails spend most of their time in flooded harvested and fallow rice fields. The affiliation of pintails to rice agriculture is not a new revelation, as pintails winter in great numbers in other major rice-producing areas of North America. Rice farming is one of the few land uses along the Texas coast that has been beneficial to waterfowl. Flooded rice fields provide pintails and other waterfowl with high-quality feeding habitat. In fact, rice fields have helped mitigate the loss of natural seasonal wetlands in many areas. Unfortunately, in Texas, increasing production costs, especially for irrigation water, have made rice less profitable for farmers to cultivate, and many rice fields have been replaced by other crops, converted to pasture, or engulfed by expanding urban areas. As a result, rice acreage has declined by about 60 percent along the Texas coast since the 1970s.
Research has also found that Texas pintails often depart their wintering grounds several weeks later than pintails that winter in other regions. This is troublesome because pintails are early nesters, often initiating nests in April before many other duck species have arrived on the prairies in large numbers. Early arrival and nest initiation allow pintails to take advantage of ephemeral wetlands that hold water for a relatively short time in spring and early summer. Consequently, delayed arrival on breeding areas may have negative impacts on pintail reproductive success.
Finally, earlier research has indicated that in some areas of the Texas coast, pintails consume foods that are low in energy, forcing the birds to rely on stored fat reserves throughout winter. As a result, these pintails are leaving their wintering grounds much leaner than pintails from other wintering areas. This may require the birds to spend more time feeding on spring staging areas to rebuild fat reserves, further delaying their arrival on breeding areas.
Collectively, low over-winter survival, reduced energy reserves, and late or delayed spring departure dates from Texas coast wintering areas may have subtle, negative effects on pintail nesting efforts and success. This may have partially contributed to suppressed continental pintail populations in recent decades. Certainly, most of the pintail decline is related to effects caused by well-documented changes in prairie breeding habitats, but data obtained through this research suggest habitat loss along the Texas coast may also be a factor.
As a result, DU and its partners are working to expand efforts to increase the amount of winter foraging habitat on the Texas coast. DU, the Texas Parks and Wildlife Department, the U.S. Fish and Wildlife Service, and the Natural Resources Conservation Service developed the Texas Prairie Wetlands Project (see sidebar) to increase the amount and quality of foraging habitat available to pintails and other waterfowl wintering in coastal Texas. Additionally, biologists are working with landowners to encourage them to keep some wetlands flooded well into spring to ensure that pintails have adequate habitat to build fat reserves for a timely migration. Through these efforts, DU and its partners are working hard to increase waterfowl habitat in this important region and allow pintails to return north in good condition and produce the next generation of these sleek, beautiful birds.
Dr. Bart Ballard is an associate professor and research scientist at the Department of Animal and Wildlife Sciences and Caesar Kleberg Wildlife Research Institute at Texas A&M University–Kingsville.