Health & Nutrition
Feeding Ecology of Wild Cockatiels
Note: this article was written specifically for cockatiels. It may or may not be applicable to other species
Csiro Publishing
has the abstract of a
scientific paper on the feeding habits of wild cockatiels in a grain-growing
district. Here's the text: The preference for any kind of soft seed over any kind of hard seed is
interesting. A study on the wild diet of zebra finches (which occupy the
same habitat as cockatiels) found that unripe seed was an important breeding
food. They noted the easier digestibility just as the cockatiel study did,
but found another important factor: the unripe seed was higher in protein
than the mature seed (Allen
& Hume). I haven't been able to find information on any other
nutritional differences between ripe and unripe seed.
The July 2000 issue of Bird Talk has an article about the cockatiel study.
Bird Talk had more to say about crop contents that isn't online: The mineral items are apparently equivalent to grit, and according to the
actual paper they mostly consisted of quartz. The paper says that the
dense woody material was found in about 4% of crops and was probably
fragments of tree trunk, bark, and leaves. The paper does not speculate
about the reasons for consuming these non-food items. Less than 1% of
crops contained insect remains. Absorbing dietary toxins is the reason
that's often assumed for eating charcoal. But I had doubts about their diet
being particularly toxic, and charcoal can interfere with the absorption of
certain vitamins (A, B2 and K). So I was never too sure that the bird
actually got a net benefit from it. But a study by
Majewska et al indicates that they do, and it's not just with plants
that are naturally loaded with cyanide and other poisonous chemicals. It's
also effective against bacterial toxins and mycotoxins. It seems to me that
these toxins might be a bigger threat to wild cockatiels than the chemical
defense of the plants. Their natural diet is mostly grass seed, and there
doesn't seem to be any species of grass that's considered toxic. But there
can be some nasty stuff that grows on grass, like ergot, and charcoal may be
useful for counteracting it.
The feeding ecology of the cockatiel Nymphicus hollandicus was studied in a
grain-growing district near Moree, in northern New South Wales, between
August 1980 and June 1982, by direct observations and monthly collections of
birds in feeding flocks. Cockatiels fed from the ground, on fallen seed or
by felling stems, and, when feeding on sorghum and sunflowers, while perched
on the seed heads. The mean size of a feeding flock was 27; large flocks of
more than 100 birds were formed only during periods of limited food supply.
Cockatiels showed a clear preference for sorghum over sunflowers, and when
on cereals they appeared to prefer softer, younger seed to harder, mature
seed. Overall they fed on 29 seed types, including four grain-crops, 17
grasses and eight non-grass ground plants. Sorghum was by far the most
important food item, making up almost 60% of total crop contents; sunflower
made up only 6% of crop contents, and grasses 19.3%; 90% of this last was
contributed by Phalarisparadoxa and Setar~a sp. Some management
implications, based on apparent food preferences, are discussed.
From the paper itself:
"cockatiels appeared to prefer soft, 'doughy' grain to harder,
mature grains... Cockatiel flocks fed without exception on grain-crops with
doughy seed, abandoning each field as it reached maturity and moving to the
next most suitable grain-crop... Although cockatiels were certainly able to
eat the mature seed, the condition of the seed in the crop contents did
indicate a preference in cereals for softer seeds. Cockatiels fed on
soft sorghum and wheat seeds whenever these were available, but appeared to
take less grain and move to other foods, i.e. grasses, as the cereal crops
matured. Grasses were important only when the available grains were
mature... Immature kernels are probably preferred because they are easier to
bite up and swallow, and are more digestible."
"Of the birds studied, there were pieces of charcoal in 29 percent of all
crops,
mineral items in 13 percent of all crops, plus dense woody material in many
of
the crops. It could be postulated that the intake of charcoal was to de-toxify
other items the birds eat as part of their normal diet. This could be for
reasons similar to why some of the macaws of South America eat clay from
cliff
faces. The intake of a bland substance must have a purpose, otherwise the
birds
wouldn't include it in their diet."
Still more from BirdTalk:
"They also attack standing crops, particularly sorghum and millet, and can
cause
significant damage. They are known to be particularly fond of acacia seeds
and mistletoe berries. They are ground-feeding birds that search for
whatever seeds are available from grasses, herbs, and trees. Cockatiels have
been seen in mixed flocks with red-rumped parakeets picking up spilled grain
in stubble paddocks.”
"Some grain farmers devised a special method of preventing cockatiels from
devouring their sunflower crops. They sowed a strip of sorghum around the
perimeter of the sunflower field, timed so that the ripening sorghum has a
milky
head just as the sunflower crop is at its peak. Because the milky head of
the
sorghum is their favorite food, the cockatiels devoured the 'sacrificial'
sorghum strip, leaving the sunflower crop untouched."
"The daily feeding routine includes a morning ritual whereby, 30 to 50
minutes after sunrise, they fly in a group from their roosting trees and
perch in dead trees with their backs to the sun, to sun themselves before
going to ground to feed. Even the late arrivals follow the same procedure
before feeding."
"The afternoon session starts 60 to 90 minutes before sunset."
Copyright 2014 Carolyn Tielfan all rights reserved