This IBA is rare desert cienega and connected creek system in southern Arizona. These wet habitats are just a small part of the Buenos Aires National Wildlife Refuge, which encompasses 118,000 acres. Arivaca IBA is located thirty miles west from the main north-south interstate highway in southern Arizona, near the town of Arivaca. The cienega is supported by seven springs. Arivaca Creek in most years is a perennial creek for 2 miles of its 5?-mile length to where it joins the Brawley Wash system.
This IBA is important in Arizona because it supports significant breeding numbers of Yellow-billed Cuckoo, Gray Hawk, Swainson's Hawk (Arivaca Creek), Lucy's Warbler, and Black-bellied Whistling Duck, and small but reliable numbers of nesting Costa's Hummingbird, Northern Beardless-Tyrannulet, Tropical and Thick-billed Kingbirds, Rufous-winged Sparrow, and Varied Bunting, all of which are Species of Conservation Status (SCS) in Arizona (11 SCS total). Sora and Virginia Rails nest within the cienega as well, rare and uncommon species respectively in Arizona. Buff-collared Nightjar another rare species, is know to nest along Arivaca Creek. Additionally, the IBA supports many conservation species in migration, such as, Southwestern Willow Flycatcher, Gray Flycatcher, Swainson's Thrush, Lucy's Warbler, Virginia's Warbler, and MacGillivray's Warbler (6 SCS in migration). In winter this IBA becomes a hotspot for Sparrows, both in terms of diversity and density, notable Species of Conservation Concern include: Brewer's ,Cassin's, and Grasshopper Sparrows. Lastly, winter brings an influx of raptors and wading birds, these include, Peregrine Falcon and Great Egret (both SCS) (5 total SCS in winter). Although, not SCS, the following other raptors (or functional raptors) and wading birds are also present in winter: Northern Harrier, Cooper's Hawk, Red-tailed Hawk, American Kestrel, Loggerhead Shrike, and wading birds: Great Blue Heron, Green Heron, and Black-crowned Night Heron. Green Kingfisher, a rare species in Arizona, has been known to winter as well.
Water table draw down by nearby water use in the nearby town of Arivaca is a concern. Buenos Aires NWR is working to attain water rights. Cowbird parasitism is likely a significant impact on reproduction performance of many species. Cattle grazing occurs on nearby lands attracting cowbirds to the area. Bullfrog spread into the cienega ponds is a serious concern, this non-native invasive species could alter the food chain structure of the cienega.
Other flora and fauna:
Research and Conservation Projects:
Protected as part of Buenos Aires National Wildlife Refuge.