FW 404: Managing Songbird Habitat, 11/4

Managing Songbird Habitat

Habitat Requirements

• Seasonal change (obligate migration)

• Food (insects, fruits, seeds)

  • insectivores

  • competition is intense in the tropics which is why birds don’t stay there year-round

• Water

• Cover

  • nesting

  • escape

  • roosting

Plant Richness = Food diversity

• Different fruits

• Different caterpillars

• Different seeds

• Influenced by management

Vertical Structure and Birds

• Different birds use different forest layers

• Ground/shrub cover is critical for many species

  • can predict the vegetation structure by just listening to birds in the area

• Midstory is the least important layer

• All are influenced by management

• Moist, fertile soil conditions increase understory when there are closed canopy conditions

Horizontal Structure

• Where two vegetation types or ages meet is an edge

• Edges are often selected

  • access to 2 vegetation types (less common for birds)

  • increased vertical structure

  • when rest of structure is poor

Cowbirds and Corvids

• Edges may attract these guys

• Especially in agriculture and urban landscapes, not in landscapes dominated by forests

Birds Specialize—Community Types

• Upland hardwood

• Bottomland hardwood

• Gum/Cypress swamp

• Upland pine/mixed p-h

• Pine woodland

• Elevation (3000’)

Birds Specialize by Seral Stage

Grassland/Shrubland Birds

• Community maybe maintained by climate

• But typically depend on disturbances

  • timber harvest and prescribed fire

  • natural disturbance

• Small window of suitability

Prairie warbler is area-sensitive and may require shrubland patches >5 ha.

Late-successional

• Require mature forest

• Often area-sensitive (forest-interior)

• May depend on internal disturbance

  • treefall gaps, beetle kills, etc

  • complex structure

Treefall Gap Specialists

• Kentucky warbler

• Swainson’s warbler

• American redstart

Non-breeding Phenomenon

• Late succession birds move to disturbed

  • more food

  • better microclimate?

  • protection from predators?

    • naive fledglings and migrants, molting adults

What are Focal Species?

• species you manage for

• ovenbirds = closed canopy forests

• prairie warbler = forests just cut down

• can’t manage for all species

Other Threats to Songbirds

• urban land conversion

• closed canopy forest

• intensive agriculture

• loss of grassland/shrubland

• feral and outdoor house cats

• loss of migration stopover area

• collisions with human structures

• loss of habitat during non-breeding in tropics

Forest Management

• Timber harvest changes the seral stage

• Prescribed fire alters structure (composition?)

• No stand provides habitat for all species

Even-aged Harvests

• Clearcut

• Young forest today is mature tomorrow

• Brief shrubland condition

• High fruit and seed production

• Fewer large (>50 acre) harvests

• 2-aged stands retain canopy structure

• Reserves can become snags

Forest Stand Improvement

• Thin to prevent crown closure

• Basal area/ canopy retention depends

• Retain snags

• Use prescribed fire when appropriate

Snags

• Woodpeckers

• Secondary users

• Roosting

• Feeding on insects

Snag Numbers

• Estimated #/acre for average population

• More is better, but don’t kill all the trees!

• 5-10” dbh

  • 0.91 in pines

  • 0.77 in hardwoods

• 10-20” dbh — 0.41

• >20” dbh — 0.06

Fire and Nesting Birds

• Concern about growing season fires

• Most species re-nest

• Patchy burns better

• Shrub-nesters

  • 3- to 5-year intervals

• Grass/forb nesters

  • 2- to 3-year intervals

Cookbook Recommendations

• Conserve contiguous forest in agr/urban

• Leave >75 ft buffers on each side

• Consider shelterwood or group selection

• Encourage vertical structure

• Leave ≥ 2, >10-in dbh snags/acre

• Promote seral stage diversity

• Leave non-crop vegetation in agriculture