Action: Translocate woodpeckers
- All five translocation programmes studied were for red-cockaded woodpeckers Picoides borealis in the southern USA.
- Six studies of four programmes found that >50% of translocated birds remained in their new sites, with two studies of the same programme reporting a large population increase.
- Birds from four programmes were reported as forming pairs or breeding, although some translocated pairs split up and some translocated nestlings were abandoned.
- One study found that translocated nestlings fledged at similar rates to native chicks.
Red-cockaded woodpeckers Picoides borealis are a vulnerable species from the southeast USA. They are subject to intense management practices including forest manipulations (see ‘Natural system modifications’) and competitor control (‘Invasive and other problematic species’). Red-cockaded woodpeckers live in small family groups, normally with a single breeding pair. These groups occupy small ‘clusters’ of trees and can become increasingly isolated if populations decline.
Translocating birds between groups and into new areas therefore represents a potential method of maintaining a viable population structure. Pine stands can be specifically managed for woodpeckers to create unoccupied clusters, into which translocated birds can be released.
Supporting evidence from individual studies
A small trial at two open pine woodland sites in Texas, USA (Rudolph et al. 1992), found that, of five translocated red-cockaded woodpeckers Picoides borealis, four remained in their release sites. One pair were moved less than 4 km within the same forest block in February 1991 and the male returned to his original group the next day. The female remained and after a second male (from another forest block) was released the pair nested successfully in both 1991 and 1992. The second pair were translocated from separate sites, released in February 1992 and appeared to remain in the area, using artificial nesting cavities (see ‘Provide artificial nesting sites’ for details). Birds were captured at their roost cavities, transported to the release site and placed in tree cavities approximately 20 m apart. Wire mesh was placed over the cavity entrances until the birds were released at dawn. Prior to translocation, resin wells at the release site were reopened and potential competitors for cavities (e.g. southern flying squirrels Glaucomys volans and red-bellied woodpeckers Melanerpes carolinus) were removed (see ‘Reduce inter-specific competition for nest sites by removing or excluding competitor species’ for details of similar removal programmes).
A small before-and-after study in a loblolly Pinus taeda and longleaf P..palustris pine forest in South Carolina, USA (Allen et al. 1993), found that 31% of 16 red-cockaded woodpeckers Picoides borealis translocated in 1987-91 died or emigrated from the release site. Adult females settled and bred more successfully than subadults (three of four adult/unknown age females bred vs. one of six subadults) and male translocations appeared less successful than female (one of four males translocated less than 20 km bred). Three nestlings translocated with their parents in 1988 died after being abandoned. By the end of 1991, the local population was six breeding pairs and 15 other birds, compared with one pair and two other birds in 1986. This translocation programme is discussed further below. Competitor species were removed from release sites (see ‘Reduce inter-specific competition for nest sites by removing or excluding competitor species’) and habitats modified (see ‘Threat: Natural system modifications – Forest modifications’) throughout the study period.
A series of before-and-after trials in four open pine forests in Texas, USA (Conner et al. 1995), found that 11 of 19 translocated red-cockaded woodpeckers Picoides borealis formed pairs at their release sites. Birds were one-year-old when they were transported to tree clusters containing a single bird of the opposite sex in 1989-92. Success rates did not differ significantly between males (three out of five birds, 60%, establishing) and females (eight out of 14 birds, 57%). This study also discusses installing artificial nesting cavities and managing forests for woodpeckers, see ‘Provide artificial nesting sites’ and ‘Use prescribed burning’ for details.
A later review (Franzreb 1997) of the same translocation programme as in Allen et al. 1993 found that 63% of 49 adult and subadult red-cockaded woodpeckers Picoides borealis translocated into a very small population in 1986-95 remained at the release site for at least 30 days and 51% (25 birds) had reproduced by July 1996. Over the same period, the peak woodpecker population increased from 10 to 99 individuals and from one to 19 breeding pairs. Similarly, the total number of fledglings produced each year increased from three in 1985 to 43 in 1996 (average of 2.2 fledglings/breeding pair/year). Birds were translocated to the release site from family groups within the same forest block and from more distant sites (see below). This study also discusses the impact of intensive management of habitats and competitor species in ‘Threat: Natural system modifications’, ‘Provide artificial nesting sites’ and ‘Reduce inter-specific competition for nest sites by removing or excluding competitor species’.
A before-and-after trial in Texas, USA (Carrie et al. 1999), found that of 17 red-cockaded woodpeckers Picoides borealis translocated to an open pine forest site, 12 (71%) established territories: three (18%) at their release sites and the others an average of 2.8 km away. In total, five pairs of subadults and seven individual birds (four male, three female) were released between December 1994 and March 1995. Only one of the pairs released (20%) remained together and five birds (three male, two female) went missing. In total, eight out of nine pairs of woodpeckers newly discovered at the sites in 1995-6 (89%) contained at least one bird translocated from elsewhere. Birds were released into unoccupied ‘clusters’ (see ‘Threat: Natural systems modifications – Forest modifications’ for details), with at least three such stands within 1 km of the release site to allow dispersal. Stands were also provided with cavity inserts (see ‘Provide artificial nesting sites’) and southern flying squirrels Glaucomys volans were removed from all sites to reduce competition (see ‘Reduce inter-specific competition for nest sites by removing or excluding competitor species’).
Another review (Franzreb 1999) of the same red-cockaded woodpecker Picoides borealis translocation programme as Franzreb 1997, reported that 55% of the 189 nestlings produced between 1986 and 1995 had at least one translocated parent. Two more nestlings were fostered to other birds in the release site, see ‘Foster eggs or chicks with wild conspecifics’ for details. Above fledging age, age and sex had no impact on translocation success, but long-distance translocations were more likely to succeed, because birds moved shorter distances were more likely to return home (25% success for 12 birds moved less than 7 km; 71% for 21 birds moved 19-23 km; 81% for 16 birds moved 182-483 km). All three groups however were equally likely to breed (25%, 57% and 62% of birds breeding in each group respectively). The presence or not, of a resident male did not significantly alter release success. Birds were released directly into natural or artificial nesting cavities after translocation.
- Rudolph D.C., Conner R.N., Carrie D.K. & Schaefer R.R. (1992) Experimental reintroduction of red-cockaded woodpeckers. The Auk, 109, 914-916
- Allen D.H., Franzreb K.E. & Escano R.E.F. (1993) Efficacy of translocation strategies for red-cockaded woodpeckers. Wildlife Society Bulletin, 21, 155-159
- Conner R.N., Rudolph D.C. & Bonner L.H. (1995) Red-cockaded woodpecker population trends and management on Texas national forests. Journal of Field Ornithology, 66, 140-151
- Franzreb K.E. (1997) Success of intensive management of a critically imperiled population of red-cockaded woodpeckers in South Carolina. Journal of Field Ornithology, 68, 458-470
- Carrie N.R., Conner R.N., Rudolph D.C. & Carrie D.K. (1999) Reintroduction and Postrelease Movements of Red-Cockaded Woodpecker Groups in Eastern Texas. The Journal of Wildlife Management, 63, 824-832
- Franzreb K.E. (1999) Factors that influence translocation success in the red-cockaded woodpecker. Wilson Bulletin, 111, 38-45
- Wallace M.T. & Buchholz R. (2001) Translocation of red-cockaded woodpeckers by reciprocal fostering of nestlings. The Journal of Wildlife Management, 65, 327-333