Download
1 / 27

Colonial Breeding - PowerPoint PPT Presentation


  • 174 Views
  • Uploaded on

Colonial Breeding. Occurs species feed in intraspecific flocks on unpredictable foods Fish-eaters: herons, seabirds Aerial insectivores: bee-eaters, swifts, swallows Some seed-eaters: weaverbirds Key benefit = locating food through information center No other feeding benefits.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Colonial Breeding' - hova


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Colonial breeding l.jpg
Colonial Breeding

  • Occurs species feed in intraspecific flocks on unpredictable foods

    • Fish-eaters: herons, seabirds

    • Aerial insectivores: bee-eaters, swifts, swallows

    • Some seed-eaters: weaverbirds

  • Key benefit = locating food through information center

  • No other feeding benefits


Anti predator benefits l.jpg
Anti-predator Benefits

  • Confuse predator – no

  • Detection of predators – no

  • Danger to predator – moderate benefit

    • Works against birds, not mammals

  • Safety in numbers – moderate benefit

  • Shielding – benefit for some (dominants in center), not others (subordinates periphery)


Constraint of limited nest sites may contribute to coloniality l.jpg
Constraint of limited nest sites may contribute to coloniality

  • Safe places to nest near food source may be limited, clumped in space

  • Safe place necessary to overcome cost of having nests in close proximity


Mating system classification based on pair bonds l.jpg
Mating System Classification (Based on Pair Bonds) coloniality

  • Monogamy: each individual has 1 bond

  • Polygamy: some individuals have >1 bond

    • Polygyny: males have >1 bond

    • Polyandry: females have >1 bond

    • Polybrachygamy: both males and females have >1 bond


Mating system evolution l.jpg
Mating System Evolution coloniality

  • Monogamy evolves if x > p(y+z) + (1-p)y

  • Affected by value of (male) parental care, difference in number of young 2 parents can raise (x) relative to number 1 parent can (y)

  • Affected by probability of obtaining an additional mate (p)

  • Usually males rather than females are polygamous (eggs cost more than sperm)


Monogamy rules in birds l.jpg
Monogamy Rules in Birds coloniality

  • Monogamy is more common in birds than in any other kind of animal

  • >90% of bird species are monogamous

  • Large contribution of 2nd parent due to advanced behavioral forms of parental care that can be performed by both sexes

    • Feeding young and especially incubation

    • (x-y) large, y may be 0

    • Polygamy more common in species that do not feed young (17% vs 7%)


Complications l.jpg
Complications coloniality

  • The duration of the pair bond varies from perennial to annual

  • “Divorce” occurs, often in response to unsuccessful breeding at young ages

  • Extra-pair copulations are common, with 30-50% of the young in the nest being sired by an extra-pair male in some species


Resource defense polygyny l.jpg
Resource Defense Polygyny coloniality

  • 2nd most common mating system in birds

  • Male obtains additional mates (high p) by controlling resources valuable to females

  • Honeyguide males defend bee nests, hummingbird males defend patches flowers (provide no parental care)

  • Polygyny threshold model: territories vary greatly in quality, multiple females on best territories (Red-winged Blackbird)


Slide17 l.jpg

  • Resource defense polygyny occurs in several species in productive temperate habitats (grasslands, marshes)

  • Lots of variation in number of mates in some species (1-15 in Red-winged Blackbirds), only a little in others (a few males have 2 mates rather than 1)

  • 5% rule distinguishes resource defense polygyny from monogamy

  • Extra-pair copulations occur


Male dominance polygyny l.jpg
Male Dominance Polygyny productive temperate habitats (grasslands, marshes)

  • Males defend mating territories

  • Territories may be highly clumped on leks or more spread out in exploded leks

    • Leks in open areas (sage grouse), exploded leks in forest (ruffed grouse)

  • Females visit lek to choose a mate

  • (x-y) small due to food type, no male care, no resources for males to defend

    • Occurs in fruit-eaters (cotingids, manakins, bowerbirds, birds-of-paradise), species that do not feed young (grouse, shorebirds)


Female defense polygyny l.jpg
Female Defense Polygyny productive temperate habitats (grasslands, marshes)

  • Male defends group of females (high p)

  • Rare because females do not travel in groups when nesting (common mammals)

  • Restricted to a few pheasants, the odd systems of rheas and tinamous that also involve sequential polyandry

    • Groups of females lay eggs in a succession of nests cared for by individual males


Rapid multiple clutch polygamy l.jpg
Rapid Multiple Clutch Polygamy productive temperate habitats (grasslands, marshes)

  • Occurs in a few shorebirds (sanderling), button quail (Gruiformes)

  • High nest predation, male cares for first clutch to free female to feed to produce a replacement clutch

  • Female cares for 2nd clutch if first survives

  • Polyandry occurs when female gives 2nd clutch to new male, produces 3rd for herself


Other types of polyandry l.jpg
Other Types of Polyandry productive temperate habitats (grasslands, marshes)

  • Also restricted to shorebirds, Gruiformes

  • Associated with development of male care, female now has option to invest in young from first bond or seek additional mates

  • Not clear why male care evolved


Resource defense polyandry in jacanas spotted sandpipers a few gruiformes l.jpg

Resource defense polyandry in jacanas, Spotted Sandpipers, a few Gruiformes

Now polyandry (rather than polygyny) threshold model applies, females defend territories that attract multiple males, males care for eggs and young


Female access polyandry l.jpg
Female Access Polyandry few Gruiformes

  • Counterpart to leks, females court males at a central location

  • Females produce a clutch for which male cares, then return to courting area to seek an additional mate

  • High p (excess males available) drives evolution of this system

  • Found in phalaropes


ad