Woodswallows on the move

["Philip Veerman" <>]

Oh one other little point about why it was hard to have people deciding on whether birds flying over are at more or less than 100 metres altitude, is that it was not stated in the original chart instructions whether the shape above (just for now taking the two dimensional ground profile as a circle) was to be dome shape or cylinder shape! My belief was that deciding whether (let alone counting a flock of) high flying birds were within a dome shape of that radius, rather than a cylinder shape, would be absurdly difficult to judge, in a context where we wanted the rules of the survey to be easy, that any benefit in attempting to be so restrictive was negligible and that is why I wrote in The GBS Report as being a cylinder of air space above the chosen ground survey area. I perceived that the "no altitude limit" was the easiest way to explain it.

 

I take my site as a sort of rectangular transect of similar area to a circle of 100 m radius, this is so that I can access the small parks without trying to see into neighbourhood back yards. The same consideration as to shape above occurs, regardless of the ground survey area. More important than all that, is that observers are consistent between species and over time in the way they do their survey. 

 

That plan picture is useful but I won't re-post it.  

 

Sorry bits of sentence structure in my earlier message were poorly worded and "to help as collect" should have been "to help us collect" but I think you will understand.

 

 

-----Original Message-----
From: Duncan McCaskill [
Sent: Monday, 25 March 2013 4:37 PM
To: Philip Veerman
Cc: Canberrabirds
Subject: Re: [canberrabirds] Woodswallows on the move

Thank you Philip for reminding everyone that there is no height limit for recording birds in the GBS.

Also, the Garden Bird Survey isn't really a survey of birds just in your garden. A GBS site is 3.1 hectares (31,000 m2). The original rules stipulated a circular area around your home with a radius of 100m (area 3.1ha). This rule was later relaxed to allow a site of any shape so long as it is about 3.1ha in area. (Some simple examples: a rectangle 103m x 300m, a square 176m x 176m.)

This picture from Google Earth shows what a circle of radius 100m looks like in a 1970s Canberra suburb (Kaleen in this case - I just picked somewhere at random). [Suburbs established more recently have smaller blocks, some older suburbs have larger ones.]

 

I don't know how well anyone worked out the boundaries of their site in the days before Google Earth and Google Maps, and a circular site clearly isn't a good fit for suburbs with straight roads and property boundaries. 

[By the way, surveying a site for the GBS doesn't give anyone right of entry to any private property - you just have to make your best guess from what you can observe from public places.]

Duncan McCaskill

GBS Coordinator

On 25 March 2013 13:52, Philip Veerman <> wrote:

The instructions on the GBS chart since 1993 state: "There is no altitude limit, and no requirement for the birds to be 'using' the area". This is for three reasons:

 

1 So that we can obtain data on a wider range of species than those just frequent the gardens to help as collect structured information and reports on as many species as fit the method. It is not a survey of use of domestic areas by birds.

 

2 It is often unreasonable to be able to expect people to decide on and count whether a bird flying over is above or below 100 metres altitude, especially as that may apply to anything from the tiny but high flying Mistletoebirds to eagles and pelicans and swirling flocks of swifts at various altitudes.

 

3 To clarify and fix the instructions on the GBS chart V1 & 2 (1981 to 1993) which were ambiguous as to including high flying birds.

 

So if you were "doing a GBS chart, which I am not" it all revolves around what you mean by the word "above" in "flying about 100 meters high above". As in if it is above, they should be included. If Mark or anyone wished to contribute to the GBS and wished to use a different set of protocols to what is prescribed, well that is each person's choice, as a volunteer, although I would have preferred not. Because of the "citizen science" nature of the survey, I have regarded it as more beneficial to have people contributing in a manner not 100% compliant with the methods (provided they are fairly close) than to not contribute and us to miss out on the record input that they would otherwise add.

 

It is well understood that the approach taken by people to the GBS does vary, as do their skills in finding, identifying and counting birds. Thus it is one of the important biases that needs to be understood in terms the range of complications in understanding what use or not the project delivers. Which is why I tried to address these complications in The GBS Report.

 

Philip

 

-----Original Message-----From: Mark Clayton [ Sent: Monday, 25 March 2013 10:37 AM      To: 'Canberrabirds'
Subject: [canberrabirds] Woodswallows on the move

Morning all,

 

This morning around 1025 there was a group of around six Dusky Woodswallows flying about 100 meters high above my Kaleen house and moving in a roughly westerly direction. This is the first time I have seen them “this season” and was wondering if they are the six or so birds that are regular near the back gate to CSIRO (Wildlife etc, etc) along Bellenden Street, Crace. If I was doing a GBS chart, which I am not, these birds really shouldn’t qualify for inclusion as they are not actually in, or even near, my garden.

 

Cheers,

Mark