Arctic vs Common Terns

Before I really start, thanks for all the comments on the last blog post on Marsh, Melodious and Icterine Warbler. As a result these notes: be aware of 'slow' Marsh Warblers as they can resemble Melodious quite good and be aware that Melodious can have tick's as well. The recording I made yesterday from a Melodious Warbler in the Netherlands shows ticks, but really is a Melodious (plumage, rest of song). Note that the ticks sound different and are really part of the imitation.


Yesterday (Saturday 2th of June) Toy and me were bird watching with our main goal: moth ticks. As there is an Iceland Gull in Westkapelle, we had to go there. It's a MEGA for June :D. We first 'did' a Common Merganser, dipped the Bufflehead, scored Red Knot (shame on me), ticked Arctic Tern for the year list (more later), hit-and-run for the European Shag and straight to the Iceland Gull. We found out that there was still a Whooper Swan in 't Vroon and ticked it. Ah well, I ticked 10 species for my month list :D


More about the Arctic Tern (Sterna paradisaea). We were driving along the Flauwers Inlaag (near Zierikzee) with our windows open, when I heard Arctic Terns. You might think 'heard'? I know it as the day of yesterday. It was on Texel on the second of May 2009, a beautiful day, perfect birding weather. No, bulls#@#. At least some of it. It was that day that I noticed a different call in the tern-colony. Looked where the sound was coming from and it turned out to be an Arctic Tern. Since that day I am able to identify Arctic Terns by their call. As with my last blogpost, I was thinking about how to describe the differences in calls. To me, Arctic Terns always sound higher pitched and sharper than Common Tern, more 'kie' than 'kah'  and more 'krieeee' than 'kieerâh'. I made sonograms of the different calls and compared them to Common Terns.

The comparison in structure:

The difficult three: Marsh, Icterine and Melodious Warblers

When I was listening to recordings of Melodious Warblers (Hippolais polyglotta) in the Netherlands last week, I realised I didn't really knew handy tricks to distinguish it from Icterine (Hippolais icterina) and (especially) Marsh Warbler (Acrocephalus palustris) on sound only. Yesterday I received the question whether one recording showed a Marsh or a Melodious Warbler. So I dived into the matter. Listened to many recordings on Xeno-Canto.org, noted my thoughts on songs and tried to describe the differences between them. With the risk of making 'mistakes', here my notes (I'm not affraid to make mistakes, so please give comments!):

Marsh Warbler:
Very good imitations, surprisingly often with short 'tick'/'teck'/'zip' notes between other notes. Very upbeat pace and general sounds a little bit mechanistic. Starts sometimes with a Bluethroat-like 'tik tik tik tik tik' and then starts the waterfall of imitations with forementioned 'tick' notes.

Here a recording of Sander Bot on XC. Note the mechanical sound, 'tick' notes and the upbeat pace:


Melodious Warbler:
Clear imitations with clear tones. Imitations often have a longer timespan than in Marsh Warblers. Starts often with 'tretretretretre' or 'tr tr tr tr tr' and then the 'real' song. Pace still quit fast, but because of the clear tones it sounds rather melodious (could that explain the name? ;-) ). Sounds a bit like Blackcap and/or Whitethroat.

As example a recording of Jordy Calvet on XC:


Icterine Warbler:
Very typical for Icterine are the nasal tones which can resemble toys (the type you give to your dog or for in bath). Pace is more relaxed than in Melodious and Marsh.

An example from Icterine by Patrik Åberg (a recordist with many good recordings!). Note the quite awesome imitation of Rosefinch (around 45 seconds) and ofcourse the bath ducks:

As said: please give comments if you feel like I am on the wrong end or if you have additions!

And as a bonus a picture of Melodious Warbler made by Toy Janssen, the guy that learned me watching birds. Visit his site for more pictures during his/our adventures (www.globalbirding.com)