Infanticide and Brood Reduction in Birds By: Michael Sweene - PowerPoint PPT Presentation

Loading...

PPT – Infanticide and Brood Reduction in Birds By: Michael Sweene PowerPoint presentation | free to download - id: 3e3123-ZGFkY



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Infanticide and Brood Reduction in Birds By: Michael Sweene

Description:

Infanticide and Brood Reduction in Birds By: Michael Sweeney Ecol 484 2008 Infanticide? Infanticide very common in birds. Unlike mammals, birds employ behavior to ... – PowerPoint PPT presentation

Number of Views:58
Avg rating:3.0/5.0
Slides: 19
Provided by: eebwebAri
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Infanticide and Brood Reduction in Birds By: Michael Sweene


1
Infanticide and Brood Reduction in Birds
  • By Michael Sweeney
  • Ecol 484
  • 2008

2
Infanticide?
In Birds Intentionally causing the death of an
egg or nestling
  • Infanticide very common in birds.
  • Unlike mammals, birds employ behavior to their
    advantage.
  • Equally common among related birds and unrelated
    birds.

3
Questions
  • What forms of infanticide exist in birds?
  • What motives drive infanticide?
  • How does infanticide compare across taxa?
  • What ultimate reasons explain evolution of
    infanticide?

4
Forms of Infanticide
  • Parental vs. Non-parental infanticide
  • Egg vs. Hatchling destruction
  • Passive vs. Active infanticide

www.sialis.org
5
Questions
  • What forms of infanticide exist in birds?
  • What motives drive infanticide?
  • How does infanticide compare across taxa?
  • What ultimate reasons explain evolution of
    infanticide?

6
Motives for Avian Infanticide (Proximate
Approach)
  • Paternity Influenced Infanticide
  • Resource Influenced Infanticide
  • Sexually Selective Infanticide
  • Brood Reduction

7
Paternity Influenced Infanticide
  • A parent may kill young of different paternity,
    or even of questionable paternity.
  • Harem species
  • Bronze-winged Jacana ?
  • Monogamous species
  • Tropical House Wren
  • Palestine Sunbird

Mike Danzenbaker
Robert DeCandido
8
Resource Influenced Infanticide
  • The struggle for resources and opportunities are
    frequently motives for killing unrelated young .
  • Nest-site Limitations
  • Common Tree Swallows, Starlings, Dippers
  • Mating Opportunity
  • Humboldt Penguins, Guira Cuckoos
  • Group Dominance
  • Mexican Jays, Acorn Woodpeckers

www.animalpicturesarchive.com
www.freewebs.com
www.ejphoto.com
9
Sexually Selective Infanticide
  • Some parents will kill young in order to
    preferentially sire male or female offspring.

Eclectus Parrot (Heinsohn, et al 1997).
Encyclopedia Britannica Online
10
Brood Reduction (David Lack, 1947)
  • Parents may selectively starve young to reduce
    size of brood depending on environmental
    conditions.
  • Core vs. Marginal offspring
  • Marginal offspring provide brood insurance
  • Allows equitable nest fitness if something
    happens to Core offspring

Optimistic vs. Pessimistic Parenting?
www.avianweb.com
David Faintich
Facultative vs.
Obligate Brood Reduction
www.holdenby.com
11
Brood Reduction (contd)
  • Parental Mechanisms of Brood Reduction
  • Active
  • Evicting/Killing marginal young
  • Starving marginal young through nepotism of
    larger and/or older young
  • Nest Desertion due to loss of core eggs/young
  • Passive
  • Hatch order asynchronicity
  • Facilitating siblicide, or intentionally
    turning a blind eye

Hatch order asynchronicity
12
Questions
  • What forms of infanticide exist in birds?
  • What motives drive infanticide?
  • How does infanticide (Brood Reduction) compare
    across taxa?
  • What ultimate reasons explain evolution of
    infanticide?

13
Brood Reduction Across Avian Orders
Incidence of Brood Reduction Types Across Avian Orders Incidence of Brood Reduction Types Across Avian Orders Incidence of Brood Reduction Types Across Avian Orders Incidence of Brood Reduction Types Across Avian Orders Incidence of Brood Reduction Types Across Avian Orders Incidence of Brood Reduction Types Across Avian Orders
Facultative Obligate Facultative Obligate Passive Active Passive Active
Pelicaniformes Pelicaniformes X X X X
Charadriiformes Charadriiformes X X X
Anseriformes Anseriformes X X X
Podicepiformes Podicepiformes X X X
Sphenisciformes Sphenisciformes X X X X
Galliformes Galliformes X X
Ciconiiformes Ciconiiformes X X X
Falconiformes Falconiformes X X X X
Gruiformes Gruiformes X X X X
Columbiformes Columbiformes X X
Cuculiformes Cuculiformes X X X
Strigiformes Strigiformes X X
Apodiformes Apodiformes X X
Piciformes Piciformes X X X
Passeriformes Passeriformes X X X
14
Trends in Brood Reduction
  • Members of perhaps every bird order engage in
    some sort of facultative brood reduction.
  • Obligate brood reduction is common mostly in
    large birds.
  • Active brood reduction more prevalent in shore
    and water birds.
  • Relationship between altricial and precocial
    birds and forms of brood parasitism seems unclear.

15
Questions
  • What forms of infanticide exist in birds?
  • What motives drive infanticide?
  • How does infanticide (Brood Reduction) compare
    across taxa?
  • What ultimate reasons explain evolution of
    infanticide (Brood Reduction)?

16
Why Brood Reduction? (Ultimate Approach)
  • Environmental Instability
  • Insufficient food availability
  • Physiological/Phylogenetic constraints
  • Ovulation speed/ timing.
  • Egg Size
  • Nutrient allocation limitations.

Brood Reduction Fitness Fail-safe
17
Conclusions
  • Numerous reasons motivate various types of
    infanticide in birds.
  • Birds seem to love infanticide, and when they
    dont, they may encourage young to kill each
    other instead.
  • Parental Infanticide may be a useful tool for
    maximizing yearly fitness.

18
Acknowledgements
  • Becky Stephenson
  • Adam Radcliffe
  • Christine, Glenn and JodyLee
  • RedBull

Brief List of Works Cited
Forbes, L.S. (1991) Insurance offspring and brood
reduction in a variable environment The costs
and benefits of pessimism. Oikos. 62(3)
325-332 Gill, Frank B. Ornithology Second
Edition. 1990. W.H. Freeman and Company New
York. Mock D.W. (1995) The evolution of
parental optimism. Trends in Ecology
Evolution. 10130
About PowerShow.com