Brown Creeper

A. Status
1.Common resident in mature conifer forests in California

2.BBS trends show non-signifigant decline (-2.2 P=0.06). Non-signifigant decline in 4 of 6 physiographic regions (Sierra Nevada, LA Range, Pitt Klamath, California Foothills). S. Pacific Rainforest and Basin and Range okay? CBC data indicates significant increase of 2.2 per year (1959 to 1988 From Cornell website).

 

B. Habitat Needs

1.Breeding Season:  Most abundant in mesic old-growth (210 to 730 years old), with large diameter trees (>50cm dbh),  least abundant in young stands (55-80 year old)- Cascade region. Western Oregon study indicates increase in BRCR abundance with Doug Fir stand age.  Require diverse tree structure and species composition.
2.  Snags:  In cascade range, abundance positively correlated with densities of Doug Fir snags >50cm dbh and decay class 2 (5 to 18yr old snags).
3.Nest Site:  Nests behind loose bark, live or dead trees. Also cracks and occasionally cavities, and Pileated Woodpecker feeding holes (not necessarily cavities).

4.Foraging requirements:  There seems to be threshold of foraging efficiency and distance between trees:  as energy requirements increase (for foraging), productivity decreases (Wyoming study - Keller and Anderson 1972?).  Tree size important. Older rees have deeper furrows which means more habitat for insects which means more food for BRCR can forage on one large tree rather than several small trees. Start at base of tree and spiral up trunk until difficult to continue, then drop down to neighboring tree. Cascade study showed that BRCR preferred Douglas Fir with DBH >50cm for foraging.  Feed mostly on arthropods, spiders, grubs. Spiders in particular found to be important in one study.

5.Patch Size: Not found in moderately to heavily logged sites during the breeding season. Study in White Mountains, Arizona found they did not use a logged area in which the overstory had been removed, 160 trees per hectare remained but no Brown Creepers.   In Western Hemlock forests,  BRCR more abundant in unlogged than in buffer strips.  However, in buffer strips > 80m, BRCR abundance approached that of an unlogged site.

6.Diverse tree structure:  In Sierra Nevada, BRCR preferentially used stands with 2 components 1st: overstory of large pines and firs, predominantly Sugar Pines and Douglas Firs.  2nd: smaller dbh cedars and pines, particularly Ponderosa Pines.  This structure provided high arthropod abundance. BRCR mostly foraged on Incense Cedar, which had highest arthropod density throughout the year. Rarely forage in homogenous Doug Fir stands.

 

C. Concerns

1.Sensitivity to logging practices.
2.Reduction in late successional forest.
3.Conversion of mixed-conifer to monotypic stands (or non-suitable tree species composition).

4.Loss and subsequent failure to replant species of large, big trees.  Sugar Pines noted as example, though could be an artifact of the need for mature forest.

 

D. Objectives

1.Protect old growth.
2.Identify healthy breeding populations throughout current range
3.Understand factors affecting Creeper populations. (ie: find out needs for large trees ON territories; determine
                        suitable habitat for DEMOGRAPHICALLY healthy populations)

E. Action Items

Research

1.Model productivity and survivorship data and compare Sierra and Coastal regions.
2.Determine suitable microhabitat characteristics for high productivity (nest searching and spot mapping).
3.Study seasonal movements and limiting factors.

4.Study foraging behavior and energetics

5.Study role of fire on Creeper ecology.

6.Encourage off road point counts to verify or support BBS data.

7.Study patch size effects on BRCR abundance and productivity.

Management/Conservation

1.Recommend that managers replant mixed species.
2.Acquire/protect or designate areas for old growth or succession to old growth.
3.Maintain existing old growth.

4.Use SNEP to evaluate amount of old growth in the Sierra. Determine if this is enough to support optimal BRCR populations.

5.Comment on Sierra Nevada Framework  (draft EIS) by August 11.

6.Do threat assessment of old growth in California (TNC?).

7.Increase contiguous areas (patches) of old-growth through protection, land swaps, etc. (not necessarily currently old growth manage for succession to old growth). Manage percentage of public lands for succession to old growth.