Bluebirds, Statistics & the Scientific Method

Date: Tue, 3 Jul 2001 02:25:12 -0400
From: "Gary Springer" springer"at"alltel.net
To: "BLUEBIRD-L" BLUEBIRD-L"at"cornell.edu
Cc: "Gary Springer" springer"at"alltel.net
Subject: Red-Headed Woodpecker eggs in Chalet/ Is this typical?

Of all the courses I took in accumulating about 150 college credits, I believe the one field I studied which baffled the most students was statistics. In fact, of those students that took the two statistics courses I took, I believe all but 2 or 3 students walked away with absolutely no clue about what they had studied other than the quickly forgotten ability to put numbers into equations they really didn't understand.

This is unfortunate because someone that understands statistics has a far better chance of drawing the right conclusion about thousands of life circumstances.

The beauty of statistics is that it makes it possible to draw conclusions about an entire population that numbers in the millions by analyzing only a very small well selected sample in the hundreds. And, the mathematical reliability of the conclusion is easily computed as a percentage.

Further, increasing the sample size from a couple hundred to a couple hundred thousand will seldom raise the reliability of the conclusion by more than 5 percentage points if the samples were selected using reliable methods.

It may surprise you but a sample of thousands, even hundreds of thousands, will not yield nearly as reliable a conclusion as a sample size of two hundred if this smaller sample is more carefully selected and studied.

So. why am I writing about statistics on a bluebird list?

Because we can draw very good conclusions about many of the questions and ideas we have with the cooperation of only a few careful birders working in different locations.

So, again, why am I writing about statistics on a bluebird list?

Because I believe I have been experiencing extraordinary results. And, I believe you can help me determine just how extraordinary are these results.

I am not a large nest box trail operator. I personally and regularly monitor only about 60 nest boxes.

Despite the comparatively small number of boxes I monitor, this year I have experienced:

1) Two pairs of Eastern Bluebirds nesting 53 feet apart with no obstructions between the two nest boxes.

2) Two pairs of Eastern Bluebirds nesting about 100 feet apart at a location that is about 60 miles from those birds in number 1), with no material obstructions between the two nest boxes.

3) 10 Eastern Bluebird nest attempts by June 30 in an area that appears to consist of enough habitat for only one, or, at best, two nest attempts at a time. An area that consists of about three quarters of an acre of grass or sparse ground cover.

4) Multiple successful nestings of Eastern Bluebirds, Carolina Wrens, Carolina Chickadees and Tufted Titmice. (Tree Swallows are not yet this far south, yet)

5) A nest attempt, including eggs, by the rare Brown Headed Nuthatch which I had never seen until it came to a nest box.

6) And, finally, a nest attempt discovered just today of a bird that until this day, I had only seen three times in my entire life, the rare Red-Headed Woodpecker, with 3 eggs.

I will believe this experience is typical if of the thousands of nest boxes monitored by those on this list, there have been all of the following this breeding season:

1) 50 nest attempts by the Red-Headed Woodpecker that include eggs.

2) 10 nest attempts by the Brown Headed Nuthatch that include eggs.

3) 25 people with two pairs of Eastern Bluebirds nesting closer than 60 feet with no obstructions between them.

4) 20 people that have experienced 4 simultaneous Eastern Bluebird nest attempts by 4 separate pairs in an area that consists of less than an acre of grass, dirt, ground cover less than a foot tall or a combination of the three.

And, 5) 15 people with Eastern Bluebirds nesting in a small clearing in the forest of less than 50 feet in diameter and 125 yards away from any other appreciable opening in the forest canopy.

I would greatly appreciate your cooperation in this matter.

If you have any of these, please write the number of the event 1, 2, 3, 4 or 5 and indicate the number of times you experienced that event this year, then email it to me off-list at springer"at"alltel.net

Thank you for your cooperation.
Very Sincerely,
Gary Springer,

PS I am not interested in debating statistics or the reliability of my tests or reasoning and will not respond to any posts about these matters unless they are of a cooperative nature aimed at helping us better understand cavity nesting birds. And, in this latter case, I encourage all comments.

Writing from the foothills of the Appalachian Mountains in Northeast Georgia, further north than most of South Carolina and a bit of North Carolina.

Most extensive source of Bluebird information http://audubon-omaha.org/bbbox/bestofbbml/bblindx.htm

Real Bird Homes www.realbirdhomes.com

Date: Sun, 8 Jul 2001 08:09:05 -0400
From: "Tami Wires" twires"at"peoplepc.com
To: BLUEBIRD-L"at"cornell.edu
Subject: Re: Replies to success after fledge

I find it hard to believe that behavior (be it birds or humans or antelope!) can be be proven to the specifications of becoming a scientific fact! Birds are not predictable by any means...the posts on this list alone should suggest that. I see no reason why personal opinion should be "banned" on the list especially if it is headed by "in my opinioned", "I think", "this has worked for me"! I, for one, look to the list for opinions from those who have tried the various ideas presented in the "scientific" journals and books and websites!

Tami in Ohio

----- Original Message -----

From: G & C Statton statton"at"toolcity.net
To: BLUEBIRD-L bluebird-l"at"cornell.edu
Sent: Saturday, July 07, 2001 11:33 AM
Subject: Re: Replies to success after fledge

Chris Statton,
NW PA (41.5 N)

Gary,
First, as I've come to always say here, please keep in mind my information
is not "scientific".

In July, 1999, this area experienced approximately three (3) weeks of
temperatures between 95 - 105 (Farenheit). For this area (41.5 north), that
is extreme heat. The nestboxes in the yard sit in full sun all day. Using a
single-probe digital thermometer I tested roof temperatures and in-box temps
of two (2) nestboxes. I'll simply label them, here, as Box 1 and Box 2. Both
boxes were made of 3-quarter inch finished pine. Both boxes have 3" roof
overhangs on each side. Both boxes have 5" roof overhang on the front.Both
are of un-painted. Both mounted at the same height. The differences: Box 1
had 3 one-half inch diameter ventilation holes on each side, directly under
the roof overhang. (The holes on each side were lined up to be directly
across from each other.) The box had 4 floor vents and had no nest in it.
Box 2: had three (3) one-half inch x 4" ventilation slots (one on each side
and another on the front). This box also had 4 floor vents and no nest in
it.

I applied 'artificial-shade' roofs to these boxes after recording in-grass
ground temps of 100-107 degrees and having read that in-box temps can exceed
ambient temps by 20 degrees. There is a widening gap of 1"-3" (back of roof
to front) between the real roof and the shade roof. I tied a marker onto the
cord/wire of the thermometer probe (toward it being at the same place - i.e.
height from floor - inside the nestbox) and fed it, to the marker, through a
ventilation hole. The probe was about 3" off the floor of the box.

Then, noting time of day (so each check was at the same time of day), sun
exposure, wind (virtually non-existent), and humidity (all of which remained
constant throughout these weeks) I did some temp tests on these boxes.
(Note, the only substantial difference in these boxes was the size of the
ventilation holes.) The probe was left in the box until the digital read-out
remained essentially the same (i.e. only varying by one one-tenth of a
degree) for 15 minutes.

Box 1: temp on top of shade roof: 104 104 103
temp inside box: 89.4
91.4 93
temp between shade roof and real roof: 90.2 90.2 90.3

Box 2: temp on top of shade roof: 104 107 105
temp inside box: 87.1
88.9 87.5
temp between shade roof and real roof: 90.1 90.2 90.2

With just a little basic math (pi r-squared and length x width), the area of
ventilation of the holes v. the slots is obvious. The opening of a one-half
inch vent hole is 0.19625 square inches. The total openings of six of these
holes is 1.17 square". Each one-half inch x 4" ventilation slot has 2 square
inches of opening. Three such vents total 6 square inches (v. a total of
1.17 sq" with the drilled holes) or 5x the ventilation of the drilled holes.

Ever since, I have made sure the boxes have the larger ventilation slots
(with sealable covers for cold snaps) and artificial-shade roofs - some now
even have artificial-shade side panels on their west sides.

Admittedly, a big absence of info (I said this isn't scientific) is what
were temps inside boxes without shade roofs with the varying sizes of
ventilation holes. However, if in-box temps with shade roofs and large
ventilation holes stayed in the upper 80s, I can only imagine (yes, imagine
since I don't know) what the temps would have been with no shade and tiny
ventilation holes. Yes, I'm a big advocate of both shade and ventilation.

As for the "flying in place" inside the box . one of the vendors at the NABS
conference a few weeks ago was playing and selling a video compiled of
literally hundreds of hours of recording inside nextboxes (recorded over
several years). (Yep, I just had to have one of those tapes!) Anyhow, in
spite of cramped quarters those little goobers were indeed doing wing
flapping inside the box. Not a full flying in place, of course, but lots of
wing flapping.

In terms of how babies would know it is cooler outside than in the box. I
don't know that I'd say they "know". However, since humans often jump out of
windows of burning buildings - not necessarily knowing or thinking that
outside is better. They just know that inside isn't good and they want/need
to get away from it. Ants on hot metal may not have any knowledge of where
cooler is, they just keep running until they get away from the heat.

Sorry, I know we've been told not to give any unscientific information and
personal observations on this list, but I just can't fathom why we should
even bother having a list without them.

Date: Sun, 8 Jul 2001 10:23:23 -0500
From: "Keith & Sandy Kridler" kridler"at"1starnet.com
To: "BLUEBIRD-L" BLUEBIRD-L"at"cornell.edu
Subject: scientific facts/bluebirders/NABS meeting

Keith Kridler Mt. Pleasant, Texas

Before I get into the "scientific" subject remember that there are 360+ million people living in North America and about 360 people on this list during "good" times so EVERYONE here should be treated very special as they are literally "one in a million"! I thank each and everyone of you for spending the time to learn about bluebirds while you are learning about the people on this list! I especially wish to thank those who are brave enough to "share" their "observations" with the list and also for those who "question" these observations! This IS the purpose of this list!

At the NABS meeting there was a roll call of state groups and approximate state members and for example Minnesota has about 900 members on their mailing list with only about 500 actually from Minnesota. There is evidently a huge number of very rabid but very gentle bluebirders like Maynard Sumner out there who join as many state "groups" as he can to learn as quick as he can or simply to enjoy the fellowship of bluebirders! I believe Keven Bloom is a record holder in state memberships with over 25. I treasure getting to know BOTH of them from this list!

I can't find my notes right now but I believe all state groups and Canadian provinces don't add up to 5,000 members, add only a couple thousand more for NABS total membership (and most of these probably have already been counted a couple of times.) You can figure that only about 1 in a quarter million people are interested enough to REALLY learn enough about bluebirds to be able to save them and other birds from encroaching urban sprawl. Only about 1 in 5 million are brave enough to post to this list....EVER!!!!

Before the internet and NABS we bluebirders had to wait for the once a month bluebird column that Larry Zeleny wrote for Nature Society News or the newsletter that W.G. Duncan sent out a couple times a year that might or might not contain ANYTHING about bluebirds. Duncan was a conservationist and might write about anything concerning nature as he saw it being threatened. All of these were opinions of what these people observed!

Scientific writings in journals: OK I read through all 7 pages of the bibliography in small type found in the back of Larry Zeleny's book "The Bluebird, How you can help it's fight for survival" most of them state that they are observations or are worded to show that they are writing about a single experience they observed with bluebirds!

OK lets get picky! A.C.Bent probably wrote more information about more birds than ANYONE! His 1949 Life histories series is monumental. Much of Bent's information on bluebirds was shot down when James M. Hartshorne wrote his 1962 "Behavior of the Eastern Bluebird at the nest" that appeared in "The Living Bird". James' "research" totally rewrote and dispelled most of the early writings about bluebirds from 19081958! This was a SINGLE persons "observations" in ONE county in New York over 4 years and I quote him here;

"These observations were made during a four year period. Using the special observation boxes and blinds, I studied two pairs of wild birds in 1959 and two pairs in 1960. From 1957 through 1960 I obtained additional data on well over two dozen wild pairs and many individuals outside the nest cavity. For information on Bluebirds in the laboratory, I studied nine different pairs as follows: Two, 1958, 1959, 1960; three, 1958, 1959; four, 1959, 1960. All were housed in sound isolation chambers with one pair to a chamber." end quote

Just suppose aliens came down to earth in 1900, 1950 and 2000 and secretly studied 24 different human families in only three different parts of the globe each spot over a four year period and then tried to write a scientific paper on "Behavior of the human species at their home." Their research could be totally correct from what they observed but I believe if they landed in the Australian outback in 1900, China in 1950 and New York city in 2000 people reading the reports might laugh and if you switched locations and years they would think we were regressing! This list is sending out instant observations and thoughts of individuals sometimes as fast as they can imagine them. This is good and bad sometimes:-)

Scientific papers are ONLY as good as the information gathered!

Fact: Bluebirds are cavity nesters! This is false as they sometimes nest on the ground, in hanging baskets or on porch ledges or even in barn swallow nests.

Fact: Bluebird eggs and young perish when temperatures in the nestbox exceed 107*F! False! In some cases verified nestings go on normally when daily temperatures reach 113*F and nestboxes are in sunny locations!

A.C. Bent stated that male bluebirds incubate the eggs! False male bluebirds lack the brood patch and even when they sit on new born chicks the chicks lose body temperature so the male is NOT incubating even if he is covering the young!

This list of facts and contradicting information could go on for days! Enjoy the information offered, question the facts when you want but most of all enjoy the people behind these posts as they are truly remarkable people to care so much about the birds we all love that they will battle one another to defend the truths we are all searching for!

Remember the truths we find today will become the "myths" of tomorrow! KK

Bluebirds, Statistics & the Scientific Method

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