Executive Summary

1.  Overview

Introduction

NATURAL AREAS PROGRAM

NAP Background and  Goals

Objectives

Definitions

2. Management Approach

Goals

Values

Strategies

3. Setting

Biology

Vegetation

Wildlife

Landuse History

4. IPM

5. General Recommendation

Vegetation

Birds

Mammals

Soils, Erosion, and Public Use

6.Site Specific Recommendations

7. Monitoring

Issue GR4: Nesting birds (resident species, neotropical migrants, and other species of concern) are sensitive to direct human disturbance and human- generated changes to the environment. These species could be affected by human activities including vegetation management, recreational use, and off- leash dog use if these activities were to occur at the wrong time of year. In addition, brown-headed cowbirds (Molothrus ater) are common throughout the City and likely parasitize the nests of most species of songbirds in the area (Murphy 1999). The combination of nest parasitism and disturbance could place significant pressure on native passerine species.

Recommendation GR4a: Conduct annual breeding bird surveys using standardized point count or transect methodology to develop a list of species nesting, or suspected of nesting, in Natural Areas. This database of information would allow for the proper planning and coordination between management activities, especially tree pruning, to effectively enhance the habitat used by breeding birds.

Recommendation GR4b: Vegetation management activities (pruning, tree removal, ground cover removal, etc.) shall not be conducted during the breeding season (April I -September 1) unless a breeding bird survey has been conducted first. If active nests are discovered, a 150-foot radius avoidance buffer shall be centered on the nest site to prevent disturbance of the nesting birds.

Recommendation GR4c: If continued surveys indicate that parasitism by brown-headed cowbirds is a significant problem, a cowbird trapping and control program shall be established in coordination with the resource agencies to minimize the effects of this species.

Issue GR-5. Most of the eucalyptus forests within the system of Natural Areas are mono-cultures of these species. Aside from providing some nesting opportunities for raptors, these forests are of limited value to most bird species. This is, in part, because the understories of these forests are generally sparse and do not support a diverse array of scrub species that provide forage and shelter for ground-dwelling birds.

Recommendation GR-5a.- Promote understory diversity and complexity by installing native scrub vegetation within the existing forests. Species such as toyon and elderberry seem most tolerant of conditions in the eucalyptus understory.

Recommendation GR-5b: Thin these dense forest stands to allow additional light to reach the forest floor. Small openings cut within the forest could then be planted with native scrub and tree species to increase overall habitat complexity and provide important habitat for birds and other wildlife.

Recommendation GR-5c: Outside of the Critical Areas, non-native trees shall be planted in areas where they will provide wildlife habitat and not pose a threat to native habitats. Species to consider include, but are not limited to, Monterey pine (Pinus radiata), Douglas fir (Pseudotsuga menziesii), and elderberry (Sambucus spp.).

Issue GR-6: Nesting habitat for bird species that require cavities (e.g., wood ducks, woodpeckers, owls, bluebirds, etc.) is often limited within the Natural Areas. Natural cavities are preferred over nest boxes, but both can help support cavity-nesting species.

Recommendation GR-6a: Provide nest boxes for wood ducks at Impound Lake (Lake Merced), Sharp Park, and Pine Lake. Nest boxes shall be constructed, monitored, and maintained according to the specifications provided by the California Waterfowl Association (CWA 1999). It may be possible to get assistance with this project from the California Wood Duck Program, sponsored by the CWA.

Recommendation GR-6b: Provide nest boxes for other species such as western bluebirds, western screech owls, woodpeckers, tree swallows, etc. These shall be located in habitat appropriate for these species (e.g., bluebird boxes in the scrub and grasslands, and woodpecker and owl boxes in the forest). The boxes shall be constructed as designed, installed, monitored, and maintained as specified. Many box designs are available free of charge from conservation groups. Control of undesirable species (European starlings and house sparrows) may also be necessary to make any nest box program effective.  

Recommendation GR-6c: Snags (standing dead trees) shall be left in place unless they are a hazard to public safety. They provide important breeding habitat for cavity-nesting birds and perching sites for raptors.