Restoring native forest bird populations in human landscapes

1
Restoring native forest bird populations in human
landscapes

• John Innes
• Landcare Research, Hamilton

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Towns and cities
Farms with forest remnants
Large mainland forests
Uninhabited offshore islands
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Restoration?

• Reinstate species, eg robin, kokako, kiwi
• Increase numbers or visit-days of birds at your
  place, esp. tui, bellbird, kereru

Photo N. Fitzgerald
DoC
4
What limits bird populations?

• PREDATION
• Food supply
• Weather
• Parasites and pathogens
• Inter-specific competition
• Intra-specific competition

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Pest-proof fence
Option 1
Photo Neil Fitzgerald
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Karori Sanctuary (Wgtn 252 ha) has breeding.

• Kaka, brown teal, saddleback, robin, bellbird,
  little spotted kiwi, whitehead, weka
  and.mice.weasels?
• Maungatautari (Waikato 3,400 ha)
• Tawharanui Peninsula (Northland 588 ha)
• Bushy Park (Wanganui 98 ha)
• Horseshoe Lake (Hamilton 50 ha)

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Fences what we dont know

• Can we get all mice, ship rats, stoats from
  large forests?
• Mice reinvade (fence gaps, culverts, treefalls)?
• Ship rats, stoats reinvade from adjacent trees?
• Tell reinvasion cf eradication failure?
• Species mix of final bird community
• Spillover benefit?

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Planting




Option 2
Photo Neil Fitzgerald
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Waikato tui diet exotic species.
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Planting

• Gardens and other plantings ARE used by birds
• Clearly influences local bird movements
• Kereru move 60 km seasonally (DoC)
• Tui move 30 km seasonally (Bergquist)
• What we dont know
• Can scattered planting increase popns?
• No quantitative study of planting benefits for
  native birds in urban-rural landscapes?

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Native vegetation in Hamilton

• 1.6 of Hamilton Ecol. Dist. has natural
  indigenous vegetation
• Hamilton has habitat, of which 5 ha are in gullies
• Gullies occupy 8 of City (750 ha), of which 187
  ha are under restoration
• HCC community groups have planted in 146 ha of
  public land (in 196 parks)

B. Clarkson, K. Pudney, G. Kelly
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Pest control




Option 3
Photo David Mudge
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a) Reduce browsers
Oct. 1997
Jan. 2001
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b) Reduce omnivores
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(No Transcript)
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c) Reduce carnivores
ferret
stoat
weasel
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Dai Morgan
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Nest success of mainland forest birds with no
predator management

• 21 studies with 11 species 1975-2001
• Mean nesting success 19
• Mean failure due to predation 70
• Mean failure due to desertion 8

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Kereru response to pest control, Motatau,
NorthlandNZ Jnl Ecol 2873
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Kakepuku spring bird counts (birds/ 5-min count,
OSNZ unpub.)
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Kahu
Stoat
Feral goat
Ship rat
Brushtail possum
Feral cat
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Key predators?

• Kokako, kereru ship rats, possums
• Robins, tomtits, fantails ship rats
• Kiwi, brown teal stoats, ferrets, cats, dogs
• Blackbird, thrush, finches kahu, cats
• Skylarks, pipits hedgehogs
• Tui, bellbirds dont know
• Nothing magpies

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What we dont know

• Immigration vs reproduction as sources of
  increase
• Does dispersal undermine population increases in
  small areas? (yes, for robins in Wenderholm, 60
  ha)
• Best regional arrangement of pest control effort

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Translocate




Option 4
Photo K. Pullen DoC
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Translocation

• Ok if original decline factor mitigated
• Obvious, with zero pest density (ie fence)
• Feasible, with sustained low pest density
  (intensive pest control)
• Can captive rearing overcome natal philopatry?
• (eg get tui to nest in Hamilton)

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Wait and hope




Option 5
Photo DoC
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Conclusions

• Fences have transformed what is possible in some
  rural-urban areas
• Predator control can greatly increase bird
  populations
• Planting may increase bird populations does
  influence movements
• BUT rural-urban mgmt for birds currently leans
  heavily on research from large native forests
• More research is urgently required on bird
  ecology and response to mgmt in rural-urban areas