Thursday, 13 March 2014

Last and first birds

This post was catalysed by an emailed comment from Denis Wilson.
"My Rufous Fantails are about to leave Robbo - but how do I know when the last one has gone?  They should put up a sign: "Last RF to leave town, please turn out the lights"
I have received a comment that the array of quips which follow distract those who actually wish to read about birds.  Such readers - and they are most welcome - should click here or jump down 2 screens.

This recalled a bumper sticker seen in the US in 1981 "Would the last person to leave Wisconsin please turn out the lights."
It appears that rumours of its death were exaggerated - but I still bet few readers (including the author) of this post could find it on a map.  Here is a helpful image:
To illustrate my lack of familiarity with Wisconsin I thought the area to the North East (between the Lakes) was Canada.  I am advised by a Canadian friend that it is in fact Michigan.

The state seems to have three things going for it:
  • It is the home of the Green Bay Packers;
  • It is the home of the Milwaukee Brewers; and
  • It has a land border with Canada   Cheese.  
Denis's message also recalled a view expressed by Bill Oddie (possibly in his Little Black Bird Book) that it is much easier to get your name in a bird report for the last date of seeing a migrant than the first.  (This implies that most birders are anxious to get their names in the Annual Report: I reckon Bill is spot on with that one!)  Bill's solution to this is to record every species seen every day, which is of course both excellent practice and an indicator of OCD.

Having made one reference to great literature I should mention that the title of this post is inspired by Olaf Stapledon's book "Last and First men".  Apart from the deep and meaningful stuff in the tome I was taken by its use of a logarithmic time scale for the various elements.  It begins with an annual cycle, then decades, centuries, millennia and so forth.  I'm going to stick with annual.

Earlier in this season I posted on my Carwoolabirds blog about the arrival dates of migrants and at some stage I will try to bring the two points of arrival and departure together.  I have taken annotations in the COG Annual Bird report as indicating whether the birds could be considered migrants or not.  I have recorded 37 species in my database with a code of 'Migrant'.  The first stage was to assess what the database showed about reporting those species in Carwoola.  That is summarised in this image.

I have used the terms on the left side of this graphic as follows:
  1. Not really migrant are those species which are recorded in Carwoola in May and June in most years. It includes both Pardalotes, Dusky Woodswallow, Grey Fantail and Yellow-faced Honeyeater.  Australian Hobby is also in this group, since while it is only reported infrequently the reports do not show a seasonal effect.
  2. Vagrants are species reported so rarely that it isn't possible to comment on seasonal variation.  It includes Eastern Koel (or Pacific Koel or whatever the taxonomists are calling it this month) and Rufous Fantail.
  3. Partial migrants Rufous Whistler and Tree Martin: reported in May and June but in less years.
  4. Passage; Rainbow Bee-eater (which could be considered a vagrant) and White-naped Honeyeater both of which show a peak presence in the passage period.
  1. Winter- refers to Australian Shelduck which is most commonly reported in Winter.  This may be a combination of them Summering in the high country to breed and or changes in observer panel.  I have included Golden Whistlers which are rarely reported in Carwoola over Summer but replace Rufous Whistler in Winter: however they are rated as Residents by COG.
There are thus 19 species which I regard as 'proper' migrants.  Their main departure months are shown in this image.


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