Little Bittern

[Martin Butterfield <>]

Mark

Your message included "...with most of the records being of the same birds being constantly reported by people seeing them for the first time and putting them on the chat line. "

I'd make a couple of points in regards to this. 

The first thing is that putting things on the chatline s simply "chat".  It doesn't get the information into the COG database which requires that a data record is submitted (either an incidental record, as you later point out, or a full report).

My second point is that the issue of the same bird being reported time and time again is not a reporting problem, but an analytical issue.  Adding Duncan's first report of the Australasian Bittern to mine and saying there are two birds is obviously daft.  However having repeated information that shows:

1. the bird arrived (or, better, was first observed on) 19 June 2014 and 
   
2. left on (...was last reported on ...) 10 June (my current view, as no one has reported it since)
   

is of potential interest in reviewing the status of the species.  By way of example, I am currently writing about Plumed Whistling-Ducks in the COGAOI and there are 6 records between Jan and April 1998: however they are all between Nerang Pool and Kingston foreshores so very likely the same bird.  This is an example which suggests that while they are very mobile when they get some appealing they may stay around for quite a while.

As I contemplated this, I was reminded of a comment by Bill Oddie about recording migrants in the UK.  Everyone records the date of first arrival but few do so for the last date before departure, as that requires daily recording which is far more tiresome.  Bill's point was that he got many more mentions in his local Bird Report for last reports than first reports, and who doesn't like seeing their initials in the Annual Report?

Martin

Martin Butterfield

http://franmart.blogspot.com.au/

On 12 June 2014 14:43, Mark Clayton <> wrote:

One of the big problems with cryptic species is that they are just that – cryptic! When COG was surveying for the then proposed site for the National Museum at Yarramundi Reach, which I assisted in, I asked if anyone bothered to check the reed beds for Little (now Black-backed) Bitterns. When told “NO” I proceeded to wade chest deep through the reeds and successfully flushed a couple. Since then there have been quite a few records, often by people using canoes to scan the lake side edges of the reeds. Looking at Lake Ginninderra and the creek that flows into it (past the Crace and Giralang ponds and close to the large McKellar pond where the two current species are being recorded), there are large expanses of reeds that could easily hide both species of bittern and that theoretically are inaccessible except y boat.

 

I don’t know about the south side of town but in the newer Gungahlin suburbs there are numerous small reed and rush-lined ponds that would be quite capable of hosting both bittern species. How many people visit these on a regular basis? I don’t always agree with Philip but I think he is right in this case, with most of the records being of the same birds being constantly reported by people seeing them for the first time and putting them on the chat line. How many make it to the Rarities Panel I don’t know but all records of these species should go through the panel to make sure they are officially recorded as well as putting in something like an “incidental report form” which can be found on the COG website.

 

Mark

 

From: Philip Veerman
Sent: Thursday, 12 June 2014 2:06 PM
To: 'Wallaces';

Subject: RE: [canberrabirds] Little Bittern

 

Thanks for that. So mainly a warm month visitor. (The first RAOU Atlas suggests that too, the second RAOU Atlas is hard to perceive any trend). So is the current winter record record unusual? It does beg the question though about counting the number of records by month. Are these separate records? How real are these data in terms of the species presence? In this species I perceive that there would be very few separate events. The species is rarely here and when here many people go to find it. So there may well be a lot of recounting of the same birds in this graph. Which can make a trend look bigger than it should.

 

Philip

 

-----Original Message----From: Wallaces Sent: Thursday, 12 June 2014 12:48 PM      To: 'canberrabirds'      Subject: RE: [canberrabirds] Little Bittern

Previous records of Australian Little Bittern are all from October to March. The graph below shows the number of records by month for the period 1 July 1981 to 30 June 2013.

 

Steve