Sophia’s Indonesia Trip, Day 3 (Sept 2009)
On day 3 of my Indonesian vacation and our first day on Bali, we stop and visit Bird Park. The park has the standard variety of parrots, most of which are also present at other zoos. But they have a large collection of hornbills, which most other zoos do not. These large birds form monogamous pairs and live in tree holes and crevices. When the female is ready to lay eggs she builds a wall of mud and droppings to seal the opening and seals herself in. The opening is only large enough for the male to deliver food to her and the chicks. When the chicks are too large for the crevice, the female breaks out and both the male and female find food for the chicks. The female may stay in the crevice for up to 100 days!
One impressive characteristic of hornbills is the heavy, powerful bill, which they use for capturing prey, breaking open fruit/nuts (hornbills are omnivorous), building the nest, and fighting. All hornbill species have a hollow structure called a casque on the top of their beak. In most species with large casques, the casques have hollow openings and may serve as a resonator or amplifier for their vocalizations. One hornbill species, the rhinocerous hornbill, has a more solid casque, which it uses while fighting during flight.
Here’s a cassowary, which is a flightless bird related to the ostrich (from Africa) and emu (from Australia). They have feathers but these feathers lack barbules, the part of feathers that act like a zipper to keep the pieces together. As a result, the cassowary feathers are soft and fluffy rather than holding their shape the way a flighted bird’s feathers do.
Cassowarys are solitary whereas ostriches and emus live in flocks. As breeding season nears, the female becomes more tolerant of males. Males court females by strutting in a circle around the female and calling to her in a series of loud booms. If the female likes the male she’ll form a pair bond and mate. The two stay together until the female lays eggs, which she places in a pile on the ground in a shallow nest made of leaves. Once the female has laid her green eggs, she moves on, leaving the male to incubate the eggs and look after the hatchlings. Like the female emu or ostrich, she may then find and breed with another male and lay another clutch of eggs. So the cassowary mating system is serial polyandry, meaning the female bonds and mates with multiple males in series.
The male cassowary sits on his nest for up to 2 months. Once the chicks hatch, he leads them to his regular feeding grounds and protects them. They may stay with him for up to 16 months before they disperse, which the male encourages them to do by chasing them off.
As an aside, this mating system is a little different from ostriches. Ostriches live in mixed age and sex groups. Males mate with numerous females who lay their eggs in a group nest, but they only pair with one of these females-who is called the major female for that nest. The major female’s eggs sit near the center of the nest, and she may roll the eggs of other females out of the nest. In the wild, females seasonally lay eggs every two days for about 4 weeks. The breeding seasons varies depending on geographic location. Clutches in the wild may contain 12-23 eggs from 3-5 different hens with up to 11 eggs from the “major hen.” Since birds lay eggs in additional nests, though, this count may be higher than noted. In captivity, domestic birds can average 70 or more eggs per season.
Humans Leaving Their Mark
As usual, humans have difficulty leaving things they way they found them. Here, humans have graffitied the fruit.
Overall Impression of the Park
While the birds and the actual park are beautiful here, the signs and educational shows are more about providing photo opportunities than providing information. If you really want to know about the different types of birds, look up birds of Indonesia before you go. Most of the information I’ve presented here is information I already knew or looked up.
While many parrot owners let these beautiful birds ride on their shoulders, most owners
specializing in bird or animal behavior as well as skilled bird trainers avoid letting them ride like this.
Even friendly birds can become aggressive and easily poke the closest thing to their beak. For instance, if the bird becomes angry or scared at another object it may redirect it’s aggression to your face (note the proximity of your eyes to the parrots beak). Or when a bird is trying to keep its mate from interacting with another individual, it frequently directs aggression towards its mate. Birds raised by humans may view their human as their mate and try to keep the human mate from interating with others.
Note: Stay tuned for more blogs by Sophia Yin on her Bali trip at drsophiayin.com/blog.