Kookaburras, too

More family members

These two kookaburras were in the western portion of the Edward Hunter Heritage Bush Reserve at Easter. They appear to have an eye stripe quite similar to those of the two kookaburras of the previous posting.

Legge (2004) explains that the brown eye stripe is distinctive for individual birds. Further, the eye stripe shape seems to be heritable because kookaburras of the same group often have similar ones. The eye stripes of these four are similar although that of the fourth is a little different having a slightly upward slant.

What do you think?

Differences between individuals

The left adult has the blue rump often attributed to the male of the species and the one on the right is brown rumped, often attributed to the female.

As Legge (2004) explains, this is not always the case, as blue and brown can be the case for either male or female.

What is different about these two is their size. The one on the right is quite a lot bigger than the blue rumped one. This may make the one on the right is an adult female. Females are 13% heavier than males. Males are therefore relatively more capable at changing direction and shifting backwards and forwards out of the nesting hollow. They spend more of their time incubating the clutch of eggs and provides more of the food to the nestlings than the female does.

References

Legge, S. (2004) Kookaburra: King of the bush. CSIRO Publishing: Collingwood

See previous posting, Kookaburras at Easter

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