[obol] My current thoughts on VGSW infanticide

[Pat Waldron]

Dear Floyd,
    Thank you for your additional information. I have raised Silkie Bantams,
as they are great setters, as well as great egg layers. I talked to one of
the PH.D s at OSU, when they had a poultry department, about hen setting
behavior. I was told that females go into a trance, when setting on eggs.
They lay a few eggs, and the sight of a cluster of eggs triggers something
in the brain, hormones, that makes them want to do nothing else but set on
them. When they come out of this trance, is debatable. I noticed when some
early chicks hatched, they fell out of the nest box and where on the ground
right next to the nest box, and the mother was not responding to the chicks
at all. This was in spring , it was cold, and the chicks were going into
hypothermia. I decided to remove the nest BOX, and place the nest level on
the ground so the chicks could get back under the hen, with out climbing
four inches up the edge of the nest box, which they were unable to do. This
worked.
     After experiencing many different hens raising many broods, I realized
how varied they are, especially first time mothers. Some mothers would wait
until the last egg hatched, before attending to all of her chicks, others
would come out of  the trance after a few had hatched, and desert the rest
of her nest eggs.  They don¹t get to read the book.
    I recall one first time hen, who did not bond with her brood. It was the
Rooster who they went to, for warmth and comfort, and he was great!
    I have talked to other people who raise a small flocks of Bantams, and
was surprised to find that they blamed the hen for letting the first chicks
die of hypothermia. Don¹t use a nest box on the ground, and see if the first
hatched can get back under the hen. Yea, it works.
      Floyd, whether Violet-greens are controlled by similar hormones, I do
not know for sure, but I would think there would be some influence. You may
be right that she was hormonally connected to her last egg, and did not bond
to her chicks. 
    Thank you for sharing your information and thoughts on OBOL.
    Pat Waldron
    East of Scio
    Linn Co.

 

> From: "Floyd Schrock" <fschrock at macnet.com>
> Date: Tue, 4 Jul 2006 19:07:55 -0700
> To: "Oregon Birders" <obol at lists.oregonstate.edu>,
> <YamhillBirders at yahoogroups.com>
> Subject: [obol] My current thoughts on VGSW infanticide
> 
> If you are not interested in any further discussion about avian infanticide,
> please hit "delete" now.
> 
> I appreciate all the numerous comments, most of which came directly to me
> rather than through OBOL, regarding the swallow infanticide that occurred in
> my nestbox.  I can't possibly reply individually to all, so (assuming there
> is some general interest in the subject) I will reply in this way with a few
> of my recent observations and thoughts.
> 
> Most who have responded have suggested that the female Violet-green Swallow
> that killed the nestlings might have been an individual trying to find a
> mate and a nest site, and found an opportunity when the original female
> disappeared.  (I have never observed two females near the nestbox at the
> same time since April when they were sorting themselves out among the
> available boxes.)  Of course, it's common knowledge among animal watchers
> that in many species the young are eliminated in the course of such a
> takeover.
> 
> I wish I could find any shred of evidence in my photos, videos, notes and
> comments during recent weeks to support that supposition, but as I review
> the images and notes I can find nothing pointing in that direction.  It
> seems, rather, that everything points to an aberration in this individual
> due to some as yet undetermined cause.  One possible cause that has been
> suggested is the presence of the camera, and I am certainly willing to
> consider that.  However, the pair that nested successfully in the same box
> last year never seemed to mind the camera  (of which only about one circular
> square inch is visible from inside the box), and I know that there are many
> cameras placed near nests around the country.  However, I did install a
> different camera this year, and for all I know, it might be emitting a
> high-frequency sound that disturbed her.  Not sure how I might be able to
> investigate that.
> 
> But my hunch, from things that I and my family noticed during recent weeks,
> is that there is a malfuntion in the brain of this female.  Within a day or
> two of the hatching of the young birds, my son commented that she seemed to
> be very rough on them, and I had noticed the same thing, but preferred to
> assume it was just her normal mode of operation.  She seemed to be tumbling
> them around in the nest in what I thought was just enthusiastic diligence in
> finding fecal sacks to carry out.  Her search (if that's what it was) would
> continue at intervals for several minutes without finding much when the
> nestlings were very small.  On one occasion it seemed that she swallowed
> something she had found.
> 
> An alternative explanation that came to mind was that she was fixated on
> incubation, and when the eggs disappeared she became anxious and was always
> searching for them.  In fact, one of her six eggs never did hatch; it just
> stayed down in the bottom of the nest under the nestlings.  Maybe her
> digging around under the young birds was her effort to turn that egg over
> periodically.
> 
> Reinforcing that thought was her behavior during the very hot days around
> June 25.  Then, when I would have expected her to stay off the nest, she
> continued to brood them, spending several hours at a time keeping them
> "warm" when it was about 100 degrees outside, and bringing in almost no food
> during that time.  Then on June 26 she ejected two of them from the nest,
> and in photos taken after that time I cannot be certain whether she is
> feeding them or beating them up.  I do know that the male continued to feed
> them during that time, but on June 30 when she got serious about getting rid
> of them, she would not allow him to enter the box.
> 
> This is where my thinking is today, but I'm still open to, and hoping for
> further enlightenment, continuing to welcome comments and alternative
> interpretations.
> 
> I have placed two photos at the following link for those who might be
> interested, but please be forewarned that they are not pleasant to look at
> if you want to think of Violet-greens only as cheerful, friendly neighbors.
> Alan's term "wickedness" may also be appropriate at times.
> 
> http://www.sites.onlinemac.com/fschrock/Special.html
> 
> =====================
> Floyd Schrock
> McMinnville, Oregon  USA
> fschrock at macnet.com
> 
> 
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