CALIFORNIA RICE
A California Riceland Success Story
Numbers of both wintering and breeding American Bittern bitterns likely declined greatly in the Botaurus lentiginosus Central Valley with the dramatic loss of historical wetlands. The species has since adapted to the large expansion of rice cultivation in the Sacramento Valley since World War II and subsequently its population size appears to have increased. Hopefully additional research will better determine American Bittern the bittern’s population size and how this Botaurus lentiginosus species benefits from rice cultivation.
Current and past population data No estimates are available for the size of this species’ population or its densities in suitable habitat in California or the Central Valley. Limited data indicate that bittern populations in these regions have been relatively stable since the late 1960s.
Information regarding each species’ benefit to rice growers No documented benefit, but it is possible that bitterns consume some invertebrate pests in rice fields. Species in focus
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www.calrice.org American Bittern Botaurus lentiginosus
Appearance
Size: 24– 33 in Weight: 13–18 oz water but sometimes over dry ground in struc- turally-comparable herbaceous cover in uplands A medium-sized heron with a compact body and surrounding a wetland basin. Birds foraging in neck and relatively short legs. Plumage mainly rice fields likely nest in denser and taller vegetation brown above, with flecks or streaks of black, in nearby canals or weedy upland fields. buff, and cream color, and heavily streaked with brown, white, and buff below. Brown crown, Food/feeding and black streak from below eyes down side of A solitary feeder that relies more on stealth and neck (lacking in young birds). camouflage rather than aggressive pursuit to Conservation Status capture prey. Usually stands motionless, then The North American Waterbird Conservation Range slowly stretches neck and bill downward culmi- Plan considers the American Bittern to be of Most of the North American nating in a sudden dart to seize prey. Their diet “High Concern.” General protection provided population breeds in central consists mainly of insects (mostly aquatic, but by wildlife laws such as the federal Migratory and southern Canada and also grasshoppers), frogs and salamanders, fish, Bird Treaty Act. the northern United States crayfish, snakes (mainly garter and water), small
and migrates south to winter mammals (mainly voles) and a few crabs, spiders, in the southern United States, and other invertebrates. Mexico, and portions of Benefits of rice cultivation WINTER to species/group SUMMER the Caribbean and Central YEAR ROUND Behavior America. Occurs year round In the breeding season, bitterns forage extensively The combination of birds standing tall with on the mid-Atlantic coast and the Pacific coast in the shallow waters of rice fields, the extent of bill pointed skyward, their brown and buffy from southern Washington to central California, which has increased greatly in the Sacramento coloration, and ventral streaking enable them to including the Central Valley. Valley since the middle of the 20th century. blend imperceptibly with reeds and other dried marsh vegetation. Birds occasionally strike this Habitat pose when in the open, seemingly oblivious to Additional benefits of adjacent Occupies a variety of mainly freshwater wetlands the lack of disruptive background vegetation to managed wetlands to species/group with tall emergent vegetation and abundant complete their camouflage. Sometimes called Adjacent wetlands provide some additional prey. More numerous in larger wetlands, using “thunder-pumper” in reference to their breeding foraging and nesting opportunities, but these are habitats with relatively shallow water. Typically calls of low, resonant syllables preceded by limited during the summer breeding season when nests solitarily in dense marsh vegetation over clicking and gulping sounds. the extent of flooded wetlands is at an annual low.