Koels

["Philip Veerman" <>]

Notwithstanding Jack's earlier comment about the silence of the Campbell Park Channel-billed Cuckoo. (Which is a juvenile so that explains its behaviour....... )

I am in agreement with Martin's suggestion put as a question. Or maybe Martin is agreeing with previous suggestions. I'm not sure. I once again attach the extract from the GBS Report, that pretty much says what Martin is asking:

Common Koel Eudynamys scolopacea

This cuckoo has arrived here increasingly in recent years................ Maller & Jones (2001) in Brisbane found a temporal pattern to their calling which will impact on recording rate. Seasonal pattern is very clear, arrive in October, build to a December peak then decline, last observed in February.

 

(The last sentence is of course about Canberra, not Brisbane).

 

And the reference is

Maller, C.J. & Jones, D.N. 2001, ‘Vocal behaviour of the Common Koel Eudynamys scolopacea, and implications for mating systems’, Emu 101: 105–112.

 

One of the limitations of GBS data (well indeed probably most bird survey data) is that it does not distinguish between means of detection. This is an issue I discussed in detail in the GBS Report as possibly biasing data. Some species are particularly subject to this possible bias, this is an obvious one, the boobook is another. Maybe the question could be advanced by asking which of the GBS observations are based on visual, or heard, observations or both, or even visual observations that occur only by hearing them and going searching.

 

Philip

 

-----Original Message-----From: martin butterfield [ Sent: Sunday, 23 January 2011 1:25 PM
To: Jack & Andrea Holland     Cc:       Subject: Re: [canberrabirds] Koels

Koels everywhere start to get scarce
soon after the New Year as shown in the attached GBS Chart.  

NB:
the data are plotted according to a sequential week number where the week
beginning 3 July is week 1.  This avoids the series being split by the
sorting rules of EXCEL but  the NEW Calendar year starts with Week 27 not
the usual (for GBS Year) week 1.

I wonder to what extent the Koels are
under-reported in later weeks of their time here if they go a bit quieter? 
This thought was stimulated by Jack's earlier comment about the silence of the
Campbell Park Channel-billed Cuckoo.  

Martin