Yellow-Billed Cuckoo
(Coccyzus americanus occidentalis)
- DESCRIPTION
- DISTRIBUTION
- HABITAT
- CONSERVATION
- MULTIMEDIA
General Description
The yellow-billed cuckoo (Coccyzus americanus occidentalis) is a slender, long-tailed bird that is 10-12 inches in length (26-30 cm) and weighs 2-2.3 oz (55-65 g). Cuckoos have two inner toes pointed forward and two outer toes pointed backwards. The head and upper parts are plain grayish brown, faintly glossed with olive. Under parts are dull white, faintly shaded with pale bluish gray or pale buff. It has a long, graduated tail (about 6 inches or 15 cm), plain grayish brown above and black below. Outer tail feathers are broadly tipped with bright white, giving the appearance of 6 large, white spots on the underside. Distinctive tail pattern is noticeable both in flight and when perched. Wings are plain grayish brown above. The moderately long, curved bill has a hooked tip, the upper bill is black, and the lower bill is yellow to orange yellow at the base with a dark tip. The legs are blue-gray. Cuckoos are sexually and seasonally the same in plumage. Juveniles generally resemble adults, but have wing coverts tinged with cinnamon brown and a less distinct under tail pattern.
Legal Status
The western distinct population segment of the yellow-billed cuckoo was federally listed as threatened under the Endangered Species Act on 3 November 2014 (Federal Register /Vol. 79, No. 192 / Friday, October 3, 2014 /Rules and Regulations). In California, the western yellow-billed cuckoo became listed as threatened in 1971. In 1987, the species became listed as a Status 1 species (Critically Imperiled, Endangered) by the California Department of Fish and Game. In 1988, the western yellow-billed cuckoo became listed as threatened by the Arizona Game and Fish Department. The western yellow-billed cuckoo is considered a threatened species in Utah. In Nevada, the species is listed as critically imperiled and is proposed for protection as threatened. Currently, it is listed as endangered by the Nevada Natural Heritage Program.
Taxonomy
Recent genetic studies have not found evidence supporting separation of the western and eastern populations of yellow-billed cuckoos into distinct subspecies. In 2001 and later supported further in the proposed federal listing of the species in 2013, the USFWS determined that there was sufficient information to consider the range of the western subspecies as a distinct population segment.
Reproduction
The onset of breeding is apparently correlated with an abundant local food supply or periods of greatest rainfall. Cuckoos may not breed if local food supply is inadequate on breeding grounds following spring migration. The breeding cycle is extremely rapid and requires only 17 days from egg-laying to fledging of young. Nesting activities take place between late June and late July, but may begin as early as late May and continue into September. Nest building typically takes 2-4 days. One brood of two to three young is raised per season. Cuckoos will occasionally double-brood in western populations if abundant food resources exist. Incubation begins with initiation of the first egg laying, known as asynchronous hatching, resulting in eggs and nestlings at different developmental stages in the same nest. Asynchronous hatching permits survival of the oldest nestlings in the event of a food shortage. The incubation period for yellow-billed cuckoos is 10 to 12 days. The young are fed large food items for the 5-8 day nestling period. Most young cuckoos leave the nest on day 6. After fledging, the young are dependent on the adults for at least 2 weeks.
Diet
Yellow-billed cuckoos usually glean prey items from foliage or branches, but sometimes hover, catching prey in flight. Yellow-billed cuckoos feed primarily on slow-moving insects, including grasshoppers, crickets, katydids, caterpillars, and various bugs and beetles. Larvae of the sphinx moths are noted as an important food source for yellow-billed cuckoos, and the lack of such prey is implicated in the decline of the western subspecies. Food resources vary greatly from year to year and have a significant impact on reproductive success.
Threats
Yellow-billed cuckoos face a variety of threats, including habitat degradation, pesticide use, predators, and during the nest building and egg-laying stages, cuckoos can be very sensitive to human disturbance. Population declines have been caused primarily by native riparian habitat loss through degradation and fragmentation from lowered water tables, replacement by nonnative trees, grazing practices, and river management. With small populations fewer than 25 pairs, stochastic events could cause localized extinctions. Studies indicate that even small pesticide loads in this species can cause significant eggshell thinning. Pesticides, especially used in mosquito control, could be a major threat when applied on a widespread area (especially aerially). The direct effect of pesticide poisoning, especially of cuckoos nesting in or near orchards, can be significant. Predators include Cooper’s hawks, red-shouldered hawks and northern harriers.
More Information
Additional information on this species, as well as source documentation, can be found in the species accounts located at this link (PDF). The Conceptual Ecological Model (CEM) can be found here (PDF). Technical Reports on this species can be found here.
Updated December 30, 2016
Historically, the western population of yellow-billed cuckoos occupied and bred in the formerly extensive riparian zone from southwest British Columbia, Washington, Oregon, southwestern Idaho, California, Nevada, northern Utah, central and western Colorado, Arizona, New Mexico, and western Texas, and south and west to southern Baja California, Sinaloa, and Chihuahua in Mexico. Like many riparian obligate species, the breeding distribution and number of the western population of yellow-billed cuckoos has declined in the past 80 years throughout western North America. The initial decline was most likely linked to the extensive loss of riparian habitat within the western breeding range of the species. During the late 1800s and early 1900s, large areas of virtually continuous riparian habitat in the western United States were destroyed by human activities, including conversion to agriculture, submersion under reservoirs, and channelization for flood control. Along with local declines, there was an overall range contraction.
The image below shows the distribution range of the western population of yellow-billed cuckoo.
The western yellow-billed cuckoo is known to breed in California, Arizona, New Mexico, extreme western Texas, Sonora, Chihuahua, and irregularly to Zacatecas, Mexico. Western yellow-billed cuckoos have been detected on the lower Colorado River at: Lake Mead Delta; Topock Marsh; Beal Lake Conservation Area; Topock Gorge; Bill Williams NWR, south of Ehrenberg, AZ; Clark Ranch; Palo Verde Ecological Reserve Conservation Area, and other habitat north of Blythe, CA; Cibola NWR; Paradise Valley; Adobe Lake; McAllister Lake; Imperial NWR; Picacho State Recreation Area; Martinez Lake, below Imperial Dam; Laguna Dam; Gila River confluence; Morelos Dam; Hunter’s Hole; and Gadsen Bend.
The western population of the yellow-billed cuckoo has been associated with cottonwood-willow dominated riparian habitats, with the majority of nests located in willows and, to a lesser extent, in Fremont cottonwoods. Cuckoos have been found nesting in tamarisk and mesquite, with nests generally concealed by willow foliage, but are also concealed by other types of vegetation. In Utah, western Texas, New Mexico, Arizona, and southern California, the cuckoo prefers desert riparian woodlands composed of willow, Fremont cottonwood, and dense mesquite for breeding habitat. Cuckoos in Arizona were found along lowland drainages with multi-structured native riparian woodlands containing a variable combination of cottonwood, willow, velvet ash, Arizona walnut, mesquite, and tamarisk.
On the lower Colorado River, cuckoos face extremely high midsummer temperatures that would kill unprotected eggs, and, therefore, is likely a nest-site specialist. Mature cottonwoods, with willows forming a sub-canopy layer, provide the best shading of any riparian habitat, and provided the optimal habitat on the lower Colorado River. Isolated willows or cottonwoods, mixed with tall mesquites, were also used but to a lesser extent. Standing water in many cottonwood-willow habitats may help lower air temperatures by evaporative cooling.
In the arid Southwest, breeding populations of yellow-billed cuckoos are restricted to river bottoms, ponds, swampy places, and damp thickets where humidity is relatively high. It has been suggested that nest sites were restricted to river bottoms because of humidity requirements for successful hatching and rearing of young. Foraging typically occurs in areas with a greater overall foliage density than in areas where nesting occurs.
LCR MSCP Conservation Measures
The Habitat Conservation Plan provides conservation measures specific to each species. Listed below are the species specific conservation measures for the yellow-billed cuckoo. Click on the arrows to expand the table.
| YBCU1—Create 4,050 acres of yellow-billed cuckoo habitat |
Of the 5,940 acres of created cottonwood-willow, at least 4,050 acres will be designed and created to provide habitat for this species. Created habitat will be designed and managed to support cottonwood-willow types I–III that provide breeding habitat for this species. The created cottonwood-willow would also function as migration habitat for birds that migrate along the LCR. A total of 2,700 acres of created habitat will be designed and managed to provide both yellow-billed cuckoo and southwestern willow flycatcher habitat, and 1,350 acres will be designed and managed to specifically provide habitat for the yellow billed cuckoo. The created habitat will be established in patches as large as possible but will not be created in patches smaller than 25 acres to achieve, based on the best available information, the minimum habitat patch size requirements of the species. Of the 1,350 acres of habitat to be created specifically for the southwestern willow flycatcher (Section 5.7.2 in the HCP), patches that support cottonwood-willow types I–III of at least 25 acres will also support habitat for the yellow-billed cuckoo. In addition to the spatial replacement of affected habitats, the quality of created habitats will be substantially greater than affected habitats that are currently dominated by saltcedar. Cottonwood-willow land cover created to provide yellow-billed cuckoo habitat will be designed and managed to provide high habitat values for this species. Created habitat will be dominated by native riparian trees (i.e., cottonwood and willow trees), support a tree structure corresponding to structural types I–III (i.e., the greatest proportion of trees are at least in the 10–20-foot height class), support a diversity of plant species, and be created to the greatest extent practicable in patch sizes optimal for supporting the species. Created habitat, thus, will approximate the condition of the native habitat of the species that was historically present along the LCR. To ensure that high-quality and fully functioning yellow-billed cuckoo habitat is created, the following design and management criteria, subject to adjustment through the LCR MSCP adaptive management process (Section 5.12.1 in the HCP), will be applied to created cottonwood-willow land cover dedicated as replacement yellow-billed cuckoo habitat.
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| YBCU2—Maintain existing important yellow-billed cuckoo habitat Areas |
The applicants, under agreements with cooperating land management agencies, will provide funding to those agencies to maintain a portion of existing yellow-billed cuckoo habitat within the LCR MSCP planning area (Section 5.4.2 in the HCP). Maintaining important existing habitat areas is necessary to ensure the continued existence of the yellow-billed cuckoo in the LCR MSCP planning area, provide for the production of individuals that could disperse to and nest in LCR MSCP–created habitats, and reduce the likelihood of future Federal listing of the species. |
| MRM1—Conduct surveys and research to better identify covered and evaluation species habitat requirements |
Conduct surveys and research, as appropriate, to collect information necessary to better define the species habitat requirements and to design and manage fully functioning created covered and evaluation species habitats. This conservation measure applies to those species for which comparable measures are not subsumed under species-specific conservation measures (Section 5.7 in the HCP). They are not applicable to species for which habitat would not be created under the LCR MSCP Conservation Plan, such as the desert tortoise, relict leopard frog, humpback chub, and threecorner milkvetch. |
| MRM2—Monitor and adaptively manage created covered and evaluation species habitats |
Created species habitats will be managed to maintain their functions as species habitat over the term of the LCR MSCP. Created habitat will be monitored and adaptively managed over time to determine the types and frequency of management activities that may be required to maintain created cottonwood-willow, honey mesquite, marsh, and backwater land cover as habitat for covered species. This conservation measure applies to those species for which comparable measures are not subsumed under species-specific conservation measures (Section 5.7 in the HCP). They are not applicable to species for which habitat would not be created under the LCR MSCP Conservation Plan, such as the desert tortoise, relict leopard frog, humpback chub, and threecorner milkvetch. |
| CMM1—Reduce risk of loss of created habitat to wildfire |
Management of LCR MSCP conservation areas will include contributing to and integrating with local, state, and Federal agency fire management plans. Conservation areas will be designed to contain wildfire and facilitate rapid response to suppress fires (e.g., fire management plans will be an element of each conservation area management plan). |
| CMM2—Replace created habitat affected by wildfire |
In the event of created-habitat degradation or loss as a result of wildfire, land management and habitat creation measures to support the reestablishment of native vegetation will be identified and implemented. |
| AMM1—To the extent practicable, avoid and minimize impacts of implementing the LCR MSCP on existing covered species habitats |
To the extent practicable, establishment and management of LCR MSCP–created habitats will avoid removal of existing cottonwood-willow stands, honey mesquite bosques, marsh, and backwaters to avoid and minimize impacts on habitat they provide for covered species. Temporary disturbance of covered species habitats, however, may be associated with habitat creation and subsequent maintenance activities (e.g., controlled burning in marshes and removal of trees to maintain succession objectives). LCR MSCP conservation measures that could result in such temporary disturbances will, to the extent practicable, be designed and implemented to avoid or minimize the potential for disturbance. In addition to implementing AMM3 and AMM4 below, these measures could include conducting preconstruction surveys to determine if covered species are present and, if present, implementing habitat establishment and management activities during periods when the species would be least sensitive to those activities; or redesigning the activities to avoid the need to disturb sensitive habitat use areas; staging construction activities away from sensitive habitat use areas; and implementing BMPs to control erosion when implementing ground disturbing activities. |
| AMM2—Avoid impacts of flow-related covered activities on covered species habitats at Topock Marsh |
Impacts on groundwater levels that support covered species habitat at Topock Marsh will be avoided by maintaining water deliveries for maintenance of water levels and existing conditions. At times, flow-related activities could lower river elevations to levels that could disrupt diversion of water from the river to the marsh. Improvements to intake structures that allow water to continue to be diverted or other measures to maintain the water surface elevation will avoid effects on groundwater elevation. Avoidance of effects could be accomplished with the purchase, installation, and operation of two electric pumps sized to the current inflow at the Topock Marsh diversion inlet. The pumps would most likely need to be operated during summer to make up for the lower flow periods. Implementation of this conservation measure would maintain existing habitat at Topock Marsh for the Yuma clapper rail, southwestern willow flycatcher, Colorado River cotton rat, western least bittern, California black rail, yellow-billed cuckoo, gilded flicker, vermilion flycatcher, Arizona Bell's vireo, and Sonoran yellow warbler. The extent of covered species habitat impacts that will be avoided by maintaining water deliveries to Topock Marsh are presented in Table 4-2 in the HCP. Maintaining water deliveries to Topock Marsh will also maintain razorback sucker and bonytail habitat associated with disconnected backwaters managed for these species. |
| AMM3—To the extent practicable, avoid and minimize disturbance of covered bird species during the breeding season |
To the extent practicable, to avoid and minimize potential impacts on covered bird species, vegetation management activities (e.g., periodic removal of emergent vegetation to maintain canals and drains) associated with implementation of covered activities and the LCR MSCP that could result in disturbance to covered bird species will not be implemented during the breeding season to prevent injury or mortality of eggs and young birds unable to avoid these activities. Table 5-9 in the HCP describes the breeding period for each of the covered species during which, to the extent practicable, vegetation management activities in each species' habitat will be avoided. |
| AMM5—Avoid impacts of operation, maintenance, and replacement of hydroelectric generation and transmission facilities on covered species in the LCR MSCP planning area |
To the extent practicable, before implementing activities associated with OM&R of hydroelectric generation and transmission facilities, measures will be identified and implemented that are necessary to avoid take of covered species where such activities could otherwise result in take. These measures could include conducting surveys to determine if covered species are present and, if so, deferring the implementation of activities to avoid disturbance during the breeding season; redesigning the activities to avoid the need to disturb covered species habitat use areas; staging of equipment outside of covered species habitats; delineating the limits of vegetation control activities to ensure that only the vegetation that needs to be removed to maintain infrastructure is removed; stockpiling and disposing of removed vegetation in a manner that minimizes the risk of fire; and implementing BMPs to control erosion when implementing ground disturbing activities. |
| AMM6—Avoid or minimize impacts on covered species habitats during dredging, bank stabilization activities and other river management activities |
To the extent practicable, before initiating activities involved with river maintenance projects, measures will be identified and implemented that avoid or minimize take of covered species where such activities could otherwise result in take. Such measures could include alternative methods to achieve project goals, timing of activities, pre-activity surveys, and minimizing the area of effect, including offsite direct and indirect effects (e.g., avoiding or minimizing the need to place dredge spoil and discharge lines in covered species habitats; placing dredge spoils in a manner that will not affect covered species habitats). |
Research and Monitoring Activities
LCR MSCP conducts a variety of research and monitoring activities along the LCR encompassing both MSCP and non-MSCP species. For a complete list of all activities, please see the Research and Monitoring Activities web page.
This gallery includes photos of this species. If you require larger photos, please contact our webmaster Michelle Reilly at mreilly@usbr.gov.
