Tuesday, 26 May 2015

A Bird Bander's Surprises

     As recently mentioned Miriam and I regularly check in with our bird banding friends to see which species they have been capturing in their mist nets.
    On Sunday they were able to show us a couple of real oddities. Firstly a Brown-headed Cowbird Molothrus ater laid an egg in the bag used to carry her back from the mist net to the banding table.

     A Brown-headed Cowbird is an obligate brood parasite and it seems clear that this individual was exactly ready to deposit her egg in the nest of a host species at the moment of capture, and since the egg was ready for expulsion from the cloacal orifice it had no choice but to expel it.

     The second unusual event is perhaps even more intriguing. The picture below shows the rectrices of a male American Redstart Setophaga ruticilla. 

     Curiously the left side of the tail shows the colour normally associated with a male, the right side the yellow tinge of a female.
     For the banders, Kevin Grundy and Ross Dickson, both of whom have a long record of bird banding, it was the first time they had been presented with this kind of anomaly.
     A couple of days earlier on a walk through RIM Park, we were treated to a splendid day along the Grand River.

     American Goldfinches Spinus tristis were busy gathering nesting material.

     A House Wren Troglodytes aedon was singing incessantly from a high perch.

     Wild Columbines Aquilegia canadensis were blooming in the woodlands.

     It was fortunate that this Willow Flycatcher Empidonax trailli was singing.

     Without hearing its vocalizations it is impossible to distinguish this species from the basically identical Alder Flycatcher Empidonax alnorum.


  1. Bonjour,

    Merci de nous faire participer à vos découvertes... J'apprends beaucoup et il y a un nombre tellement important de petits et grands emplumés !...
    Vos photos sont magnifiques. Réussir à capturer les chants et leurs interprètes c'est fabuleux.
    Je suis effectivement surprise d'apprendre qu'un oiseau pourrait être "mâle et femelle" en inspectant le plumage de sa queue. Comment expliquer cela ?...

    Un très joli billet.

    ❊ ♡ Gros bisous ♡ ❊

  2. Beautiful shots, David.
    So cute that little bird in your hand.
    Especially that the tail has two colors.
    The Wren as singing is really great.
    Best regards, Irma

  3. Hello David, interesting story about that egg. Is this bird a kind of cuckoo? And than the Redstart with the two colourd tail is amazing too. All in all you saw some wonderful birds. Love that capture of the river. It gives a good impression of the wonderful nature.

    1. It is not a cuckoo, Roos, but does exhibit the same kind of behaviour as the cuckoo with which you are familiar in Europe.

  4. Hello David,
    That must be a big surprise. Great that egg and funny the little young bird. Very cute!!
    Your last shot of that singing bird is really fantastic. Wonderful.

    Many greetings,

  5. Lovely collection,loved the surprise.

  6. Great post! I love the shot of the Willow Flycatcher singing.

  7. It was a special day for every one, getting an egg, layed during banding and seeing a 'multi colored' tail. New for the banders as well for the birders/photographers!!
    The photo of this part of the Grand River is great! Gr Jan W

  8. Splendor series and some singing that beautiful bird.
    Greetings Tinie

  9. An interesting tale of the tail David. It would seem the tail feathers of each side are of different ages - one fresh and pointed, the other paler one much more rounded and worn? However my admittedly 1987 Peter Pyle tells me that the shape of the rectrices seems unhelpful in ageing. Not much help there was I?

    Good to hear of your romantic exploits. You Canadians obviously know how to spoil a lady.

  10. Lovely birds. The egg is very pretty.

  11. Very special this tail feathers of an American Redstart. This color is not exactly red lol .... but that there are two colors in it of the masculine and the feminine side is all special!
    Delicious blog and I enjoyed :-)

  12. American Goldfinches are very beauty birds :-)