Date: 3/4/17 8:33 am
From: Daniel Scheiman <birddan...>
Subject: Re: Goldfinch counting
Glenn,

To estimate how many birds are in an area requires standardized survey
protocols such as mark-recapture or point counts so statistics can be used
to extrapolate based on the sample.

That is why for basic stationary counts submitted to eBird, whether in your
yard or in a natural area, whether during the GBBC or any time of year, your
tally for a species is the maximum number observed at one time in one field
of view during your watch period. It is the minimum, conservative estimate
you know at least that many birds are around. For birds that are moving
through in one direction, e.g. Common Grackle flocks going overhead on their
way to an evening roost, you can add up each wave with little chance of
double-counting.

Dan Scheiman
Little Rock, AR

On 3/4/17, 9:27 AM, "The Birds of Arkansas Discussion List on behalf of
Glenn" <ARBIRD-L...> on behalf of
<000001214b3fcb01-dmarc-request...> wrote:

This is the time of year where I start thinking about taking my bird feeders
down. Why? Because we get so many American Goldfinches, they empty my
feeders in a day. And I just can't afford to keep buying that many sunflower
seeds.
Plus, the grackles have found my feeders. Anyhow, to my question. From
sunup until about 1 PM, I can usually spot 20-30 goldfinches out feeding. Do
the same 30 birds stay there and feed for 6 hours straight? Or are there
many more goldfinches and they just come and go? What is the best way to get
an estimate on how many of these pretty yellow birds I'm actually feeding?
They don't stay put, they will eat for a few minutes, then something will
scare them and they all fly away, then in a couple minutes they either come
back, or another group comes in. Thanks.

Glenn Wyatt
Cabot

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