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ii) Helping-at-the-nest/den

Cooperative Breeding in Vertebrates. Two Types:. i ) Communal breeding. e.g. smooth-billed ani. ii) Helping-at-the-nest/den. e.g. meerkats. Forms of Help:. i) defend territory. Florida scrub jay. ii) excavate burrows or build nests. iii) incubate eggs. iv) feed young.

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ii) Helping-at-the-nest/den

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  1. Cooperative Breeding in Vertebrates Two Types: i) Communal breeding e.g. smooth-billed ani ii) Helping-at-the-nest/den e.g. meerkats

  2. Forms of Help: i) defend territory Florida scrub jay ii) excavate burrows or build nests iii) incubate eggs iv) feed young v) feed nursing female black-backed jackal

  3. Number of pups surviving Group size Do Helpers Help? Increase reproductive success of breeders i) correlational evidence e.g. silver-backed jackals Examples fromEmlen, S. T. 1991. Evolution of cooperative breeding in birds and mammals. In: Behavioural Ecology (Ed. by J. R. Krebs & N. B.Davies), pp.301-337. Oxford: Blackwell Scientific.

  4. Average fledglings per nest Group size e.g. white-fronted bee-eaters

  5. Reduce workload of breeders e.g. grey-crowned babbler

  6. ii) experimental evidence Species ControlExperimental Group RS Group RS Grey-crowned 7 2.40 3 0.80 ** Babblers Florida Scrub 3.8 1.62 2 0.56 ** Jays Moorhens 4.2 2.20 2 2.50 NS grey- crowned babblers Florida scrub jay common moorhen

  7. Why Stay at Home? Why Help? acorn woodpeckers

  8. Why Stay ? Lack of opportunity e.g. habitat Acorn Woodpecker

  9. Why Stay ? Lack of opportunity e.g. mates Superb Blue Wren High pay-off for staying e.g. territory inheritance

  10. Why Help? Observed Expected Number of visits by food-providing helpers r class Indirect fitness White-fronted Bee-eaters

  11. Meerkats Direct fitness Mutualism Delayed benefits Pied Kingfisher Enforcement

  12. The monogamy hypothesis

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