Lewis’s Woodpecker Nesting Research Update

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Lewis’s Woodpecker Nesting Research Update

November 20, 2014

William Blake and Kate Stone describe the 2014 nest monitoring of Lewis’s Woodpeckers.

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Lewis’s Woodpecker Nesting Research Update

This report summarizes 2014 nest monitoring of Lewis’s Woodpeckers.

We monitored nests in four areas: Woodchuck Creek, Pump Slough, Clubhouse Pond, and Northern Floodplain. We checked all historic nest areas for evidence of breeding.

We observed nests in the nestling phase from 8 June to 25 July (Figure 1). Fledging dates ranged from 10 July to 29 July, with most birds fledging in the second and third week of July.

Of the 17 nests we monitored, 100% successfully fledged young. We saw signs of territorial behavior (e.g., repeated presence of adult woodpeckers in a small area) in two areas without evidence of breeding. We don’t know if these areas had nests that failed or if the adults present were not breeding.

All four nesting areas had similar riparian characteristics, including proximity to water, a high snag density, and a multi-layered structure of mature deciduous and coniferous trees with an understory of shrubs.

Nest Characteristics

We commonly observed re-use of nest sites from previous years. In some instances, different cavities in the same tree were used. In other instances, woodpeckers used a different tree in close proximity to a previously used tree.

We monitored nests in conjunction with capturing and color-marking adult woodpeckers. We observed marked birds at seven of our nests

Most of the nests we monitored were in close proximity to other Lewis’s Woodpecker nests; no nest was greater than 984 feet from another nest, and more than half were less than 230 feet from another nest.

Woodpeckers nested as close as 85 feet from each other.

The male (left) at the Bridge Slough 1 Nest aggressively interacted with another adult woodpecker perching on his nest tree.

Four of the 17 woodpecker pairs we monitored shared their nest tree with other cavitynesting species. We could not determine co-nesting for two of the nests.

The Bald Eagle Nest tree first fledged European Starlings, followed by American Kestrels, and finally Lewis’s Woodpeckers.

At the Joint Effort Nest, the woodpecker cavity entrance was less than two feet from the kestrel nest cavity entrance, though on slightly different sides of the tree. We saw both species frequenting the area with little interaction. For example, a Lewis’s Woodpecker adult delivered food to the nest (left) while the American Kestrel nestlings approached fledging (right).

Lewis’s Woodpecker nests all occurred in close proximity to American Kestrel nests. Kestrels settled on territories and began nesting approximately a month before the woodpeckers. Kestrel fledging started before and overlapped with woodpecker fledging. We did not observe American Kestrel predation of Lewis’s Woodpeckers.

Lewis’s Woodpeckers appeared to pay little attention to the presence of American Kestrels. Both species increased their agitation levels as nestlings matured and fledged. In general, both species appeared to vocalize more in response to their partners, young, and conspecifics than in response to each other. In the picture below, a Lewis’s Woodpecker made contact with an American Kestrel perched near a suet feeder. This event was our only documentation of direct physical interaction between the two species.

American Kestrels used this nest cavity in 2013. The same pair of kestrels returned in 2014 but moved to a nearby tree, sharing their new tree with another pair of Lewis’s Woodpeckers as well as a pair of European Starlings.

As in past years, we documented high nest success in Lewis’s Woodpeckers breeding in the cottonwood riparian forests, a habitat characterized as “sink” habitat by Saab and Vierling (2001). Next year we hope to monitor and compare nest success in other habitat types (e.g., burned forest and mid-elevation forest patches). We also plan to begin monitoring earlier to better document nest failures if they occur.

The height of many of our nests precluded use of a peeper camera to monitor nest phenology and nestling development. Next year we plan to modify the peeper camera and pole system to provide a better view of nest contents.

We plan to continue the marking and re-sighting of locally-breeding woodpeckers. The presumed return of marked individuals will allow us to look at nest site and mate fidelity. For example, we know that several nest trees see repeated use from year to year, but we don’t know if the same individuals or pairs return to the same nest site. We will also be able to further examine home range size and interactions between paired and unpaired individuals.