Taking Sonja's point a step further, another possibility is that a lot of
birds die over Winter.
When I lived in the Eastern US someone authoritative expressed this in the
following terms (not rigorous but I think the concept works) :
1. At the start of a breeding season there are x birds in the US.
2. Each pair of them rears on average 2 young (which is another 'x').
3. Thus at the end of Summer there are 2x birds.
4. However by the start of the next breeding season there are only x
5. Why isn't the US knee-deep in dead birds?
The answer offered to the final question is that a lot of them don't make
it across the Gulf of Mexico! The timing of point 3 in Australia would be
April-May and the timing of point 4 is pretty much September-October.
On 19 December 2017 at 15:15, Sonja Ross <> wrote:
> Hi Don,
> One reason in Victoria is that September and October tend to be our
> wettest months so birders may possibly spend less time out birding. It
> could also be that if the birds are breeding in our spring, at least for
> part of the time, one of a pair could be sitting one eggs.
> Another could be that April is often Easter when people are often out
> camping and birding. Successful breeding would also show up in increased
> numbers then before winter.
> On 19 December 2017 at 13:38, Donald G. Kimball <>
>> Sorry Martin but are you suggesting there should be more parrot sightings
>> in Sept/Oct? I thought there were more records and birds present in
>> April/May. Perhaps I need to scrutinize my findings more. Thanks for
>> imput mate!
>> On Mon, Dec 18, 2017 at 1:37 PM, Martin Butterfield <
>> > Donald
>> > Are you adjusting for the total number of checklists submitted? If
>> > are more lists in Apr/May than Sep/Oct one would expect more records of
>> > parrots.
>> > Martin
>> > Martin Butterfield
>> > http://franmart.blogspot.com.au/
>> > On 19 December 2017 at 07:42, Donald G. Kimball <>
>> > wrote:
>> >> I use E-bird a good deal like many I suspect. I have noticed a
>> pattern in
>> >> parrot data. I looked at aproximately 30 species of parrots in NSW,
>> >> NT and noticed that there are more recordings/sightings for most
>> >> in
>> >> April/May as opposed to Sept/Oct.
>> >> I have my own ideas as to why this is so but would love some input from
>> >> local Aussies.
>> >> Thanks very much!
>> >> Don Kimball
>> >> <HR>
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