White-headed Woodpecker Dryobates albolarvatus
Version: 2.0 — Published July 9, 2020
Account navigation Account navigation
Movements and Migration
Welcome to Birds of the World!
You are currently viewing one of the free accounts available in our complimentary tour of Birds of the World. In this courtesy review, you can access all the life history articles and the multimedia galleries associated with this account.
For complete access to all accounts, a subscription is required.
Already a subscriber? Sign in
Dispersal and Site Fidelity
Natal Philopatry and Dispersal
From observations of color-banded birds in Washington, the mean dispersal distance from natal sites was 5.42 km ± 1.21 SD (range 4.1–7.4, n = 6) (67). Also in Washington, a hatch-year male color-banded on its natal site was found 35.1 km away the following year on what was presumed to be its breeding territory based on its behavior (JMK).
From observations of radio-tagged birds, in central Washington, 83 hatch-year birds (juveniles) were tracked from the ground and from aircraft from 2014 to 2018 (TJL). Aerial searches were concentrated within ~50 km of natal sites. Juveniles remained dependent on parents for an average of 33.5 d post fledging (SD = 5.5, range 22–45). Dispersal of juveniles from natal territories occurred in Aug when they stopped associating with parents and siblings. Over the year following independence, the maximum distance juveniles and second-year birds were detected from their natal site was on average 12.4 km ± 8.6 SD (range 2.0–47.2). Mean distance from natal site to site of first nesting was 9.2 km ± 5.5 SD (range 2.0–23.2). However, many individuals apparently dispersed outside of the study area and were not detected after September/October of their first year; thus these dispersal estimates are likely conservative. For individuals that could be reliably located and remained in the study area, dispersal was not a one-time event that occurred in autumn after independence. Rather dispersal-like movements occurred from Sept until breeding commenced in April and May of the following year. For example, one male dispersed 6 km south from his natal site in September, 16 km north in October, 33 km south in November, and then 33 km north sometime over the winter and by his first breeding season he was only 11 km from his natal site, even though he had traveled back and forth over a 103 km2 area in the intervening time. Second-year birds that moved across occupied territories from March–May were observed in aggressive encounters at times with the presumed territory holders. For individuals that attempted to breed, wandering behavior ceased 1–2 wk before nest excavation, suggesting that settling on nesting territories and establishing pair bonds can occur quickly.
Adult Fidelity to Breeding Site and Dispersal
Multi-year studies of color-banded birds indicate that White-headed Woodpeckers often remain on their breeding territories year round. In Washington, the mean number of consecutive years color-banded birds remain on a territory is 3.15 yr (SD = 1.4, n = 38; JMK). One color-banded individual was relocated on the same breeding territory for 9 consecutive years. However, a few cases of between-year breeding dispersal have been noted (85; see below), thus, not all birds remain on territories for life. Studies that reliably track individuals ≥ 1 year are needed to estimate rates of fidelity.
Dispersal from known breeding site appears uncommon, but needs more study. Most individuals are believed to remain on breeding sites from year-to-year. There are 3 documented instances of adults dispersing from one breeding site to another. In Washington, a color-banded female dispersed 4.6 km to another breeding site and a second color-banded female dispersed 8 km to another breeding site (85). Also in Washington, a juvenile male color-banded in the fall was observed breeding on that same territory for 2 consecutive years and then was found breeding on another territory, 1.6 km away, where he nested for 3 consecutive years (JMK). In all 3 instances, these dispersing adults crossed other territories occupied by breeding woodpeckers and did not simply shift nest locations within a single territory. Also in Washington, a radio-tagged second-year female dispersed 11.8 km from her breeding site after her nest failed, although she was depredated before the next breeding season (TJL).
Fidelity to Overwintering Home Range
Winter space use has not been formally studied.
Not truly migratory; limited wandering occurs usually within suitable coniferous forest habitat or occasionally in adjacent habitats at lower elevations. Dispersing woodpeckers will readily move through habitat unsuitable for breeding, such as subalpine forests in Washington (86). Extralimital records summarized in Distribution.
Timing and Routes of Migration
Records from outside of breeding habitats are primarily from August to April; one of the most distant lowland records from breeding habitat, in Marin County, California, was on 20 July (56). The timing of these records suggests that these are most likely immature birds undergoing dispersal.
Control and Physiology of Migration
Cause of occasional movements—whether food shortages, exceptional reproductive success, or other factors—is unknown. Local movements, perhaps not properly termed migrations, are probably undertaken for opportunistic reasons or could be attributed to dispersal, including exploitation of locally and temporarily abundant food source such as western spruce budworm (Choristoneura occidentalis) (87, 72) and pine seeds. In a long-term study of territorial occupancy in Washington, adult birds persisted on territories year-round even in years when there was complete failure of the ponderosa pine cone crop, suggesting birds do not migrate to new areas even when pine seed abundance is low (JMK). Ligon (88) suggested that immature females are most likely to wander because of behavioral subordinance. However, in Washington juvenile dispersal distances did not differ between males and females (86). Of 6 lowland records in southern California specified to sex, 3 were females and 3 were males. Thus, Ligon's hypothesis is not well supported by available information, though more study is needed.