Dennis and Tweeters,

That's a pretty impressive record of arrival dates for one locality, both
because
you never missed a year, and because the arrival dates are quite consistent
(despite your proviso). In my experience, Olive-sides are a fairly scarce
breeding
bird at sea level-- much commoner up in the mountains.

It may be of interest to compare these arrival dates with those for
Vancouver,
BC. I've been compiling arrival dates (and departure dates) for migrant bird
species for more than 30 years. The area covered is the Vancouver
checklist area, and all observers' sightings are included.

For Olive-sided Flycatcher (31 years of arrival dates), the data are as
follows:

Earliest arrival date April 20
Latest arrival date May 23
Mean arrival date May 10
Standard deviation 8.4 days

For your 14 years of arrival dates in Seattle, I calculate a mean arrival
date of May 16, and a standard deviation of only 5.7 days-- more
consistent than our Vancouver arrival dates.

The fact that the mean arrival date for Vancouver is May 10, vs. May 16 for
Seattle, is undoubtedly because we used data from all observers and
localities, not just one observer in one locality. If someone tabulated
arrival dates for all
observers in Seattle (or King County), it would probably work out to be May
10 or earlier.

Despite the fact that our earliest arrival in Vancouver was April 20, there
were
only 4 April arrival dates, versus 27 May arrival dates.

An article summarizing bird arrival dates in Vancouver from 1968 through
2004 will be published shortly in a local, non-technical journal. I am
hoping to publish a condensed version of this in a technical journal soon.
It's amazing
how much information you can extract from more than 35 years of bird arrival
dates.


Wayne C. Weber
Delta, BC
contopus at telus.net



----- Original Message -----
From: "Dennis Paulson" <nettasmith at comcast.net>
To: <tweeters at u.washington.edu>
Sent: Sunday, May 15, 2005 4:57 PM
Subject: [Tweeters] Olive-sided Flycatcher returns


Hello, tweets.

We heard the first Olive-sided Flycatcher for the year at our house in
Seattle today. Here are the first-heard dates since we've lived here.

16 May 92
15 May 93
17 May 94
26 May 95
13 May 96
11 May 97
8 May 98
19 May 99
16 May 00
9 May 01
28 May 02
21 May 03
16 May 04
15 May 05

That's a fair amount of variation, but the call is so loud and
unmistakable that I think we've usually heard it very soon after
arrival, and we've been in Seattle most Mays. I haven't tried to see if
this correlates with any climate or weather data.

Dennis
-----
Dennis Paulson & Netta Smith
1724 NE 98 St.
Seattle, WA 98115
206-528-1382