Date: 4/15/18 3:35 am
From: Jared Del Rosso <jared.delrosso...>
Subject: [cobirds] Re: House Sparrows - Boulder & metro area


I'm late to this discussion, but here's some more impressions of this bird
in westish Arapahoe Co....


In early-March 2016, I moved to west Centennial (Arapahoe) from the Cap
Hill neighborhood of Denver. Immediately, I was struck by the relative
absence of House Sparrows.



In Denver, they seemed the default small bird around neighborhoods, with
House Finches a close second. This was my impression, at least; I haven’t
looked at checklists to support it, however. At Denver Botanic Gardens,
where I spent most of my birding time, House Sparrows seemed slightly
scarcer and around in small numbers than House Finches.



In Centennial, I was thrilled that, initially, I didn’t see House Sparrows
in my yard. About two weeks after moving in, I saw my first. I see them
sporadically around my yard – though certainly more often than I report
them. But they’re by no means a daily sight.



Around Centennial, I regularly see a flock of House Sparrows at deKoevend
Park, where there’s a particular bush, near a residential feeder, that’s
usually filled with 15-20 House Sparrows. A few are sometimes near the
Goodson Recreation Center and the pedestrian bridge that crosses the Big
Dry Creek behind the Rec Center’s Parking lot. A pair is often at the top
of the hill beyond that pedestrian bridge.



In around 150 trips or so to Marjorie Perry Nature Preserve, I’ve never
seen a House Sparrow. I’m not the only one: there are only two eBird
reports of this bird at the preserve and my understanding is that those
reports are of birds in the residential neighborhood surrounding the
preserve, not the preserve itself.



House Sparrows are around west Centennial. I might get some along the Big
Dry Creek Trail or Willow Springs Open Space. But if I were doing a “big
day” in my home birding circle, I could miss them unless I made a special
trip to that single bush in deKoevend.



More compelling than my impressions, though, is what eBird data says.
Assuming I haven’t made any mistakes in compiling this data (though I may
have…don’t quote me on this), here’s eleven years of eBird data for
Arapahoe County, summarized so as to show the percent of all checklists
that include House Sparrows and the average count of House Sparrows on
those checklists that include the bird. This is 25,000+ checklists worth of
data.



The table shows that, over the past ten years, House Sparrows were reported
most frequently about five years ago. But, when seen, they seemed to show
in higher numbers a decade ago. This year, House Sparrows are reported less
frequently than at any point over the past decade (though perhaps these
numbers increase as spring, summer, and fall birding come on?). And
relatively few are seen when the bird is in fact reported.



Keep this in mind: I just summed and averaged numbers. A more careful
analysis would take into account all sorts of other things – effort,
distance covered, the fact that eBird use has changed dramatically over
time, etc. And this is not nearly as sophisticated an analysis as Doug Eddy
did for Colorado Springs with the CBC data.



HOSP

Percent of Checklists that Include HOSP

Average Count (When Present)

2008

11.2

8.9

2009

15.7

9.2

2010

12.1

7.3

2011

16.4

5.9

2012

15.2

7.2

2013

20.4

6.8

2014

18.7

5.3

2015

16.8

6.2

2016

12.8

5.4

2017

13.2

5.3

2018

8.4

4.9



- Jared Del Rosso

Centennial, CO


On Monday, April 9, 2018 at 11:48:40 AM UTC-6, ouzels wrote:
>
> Denver Audubon just received a call from a woman in Lafayette with a
> unique subject: where have the House Sparrows gone?
>
> She says she used to have as many as 80, but now she sees only a pair or
> two, sproadically. They check out her yard and continue on somewhere else.
> Have any of you experienced a diminishing numbers of House Sparrows?
>
>
> Hugh Kingery
>

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