A week to go

Firstly, apologies for no update last week from me.   I seem to get further behind each day!  Anyway, a longer one today to make up for it.

Only about a week before the first fledge is due.   By my calculation that should be about 13 November ie next Wednesday, but as you guys know, anything can happen. Sometimes one takes off early (usually, but not always, the smaller male) and some linger for days in the box.  I’ll be around next week to try and find them after fledging (in case they land in the car park, which happens!).

Note that if you are staff or student here at the uni, be careful as the female may attack you if she thinks you are too near the fledgeling.   My advice is to steer clear of the Girinyalanya area after the middle of next week! Or wear a hard hat….

The juveniles at Collins St., Melbourne are five days older than ours and have not fledged, but I expect them to do so any day now.

When they are due to fledge, the parents will try to lure them out and I expect fewer prey to arrive next week.  Mind you, that wouldn’t be hard with up to eleven prey coming in over the last week or so.  That is a deliberate tactic to make them a bit hungry and keen to come out and explore, so don’t worry if less food is forthcoming.

Now that the juvenile starlings are out, the parents, and particularly Xavier, are taking full advantage of these for the chicks.  And they are progressing well towards independence, often grabbing the prey from adult (especially, our greedy guts female, Gaia) and shielding it from the others.  Pluto is less aggressive, but is getting his share.  Here he is having a bit of a tug-of-war with his sister.   There is also considerable wing-flapping going on in the box, not to mention rock-climbing!

Our female Gaia is considerably larger than her brother, Pluto (well named, guys).   And was noticeably larger even at three weeks, when they are usually indistinguishable unless they are in the hand for banding when you can measure wing length etc.   So a big girl, or small chap!  Note also that males mature faster, so Pluto on right has more of his brown juvenile plumage than Gaia, who is still noticeably fluffy.


Larger female, Gaia, on your left, Pluto on the right

It’s interesting to ponder why females are so much larger (up to 50%) than their male counterparts.   In fact the name ‘tiercel’ comes from the older word meaning ‘one third’ ie that the male is one third smaller than the female.   I always thought this dimorphism was because she does most of the incubation, so needs to have a greater ‘spread’.  Males sometimes struggle to cover more than two or three eggs.  Other ecologists have put forward the view that it is because she can take larger prey (which is true, but doesn’t really account for the evolutionary question of ‘to what advantage’).  Another theory is that the male needs to be smaller because he is so aggressive and capable of injury while mating.  This is discounted by Derek Ratcliffe (The Peregrine Falcon, 1980) as unlikely to be the only explanation.  Perhaps it is a combination of these factors, with the nimbler male catching smaller prey and the larger female coping with the heavier ones, giving them a better spread of species, plus a size difference keeping the male in his place, so to speak.  I have to admit, I don’t really think of Xavier as aggressive.  He always demurs to Diamond!

The week before last I gave a talk about this project in Sydney to a group of interested Sydney-siders as they have a pair of peregrines using the Circular Quay area.  The tour was fully booked, mostly with families which was nice.  We tried to find the pair, and their nesting spot, without success, alas, then adjourned to the Customs House where I gave myPeregrine project talk for website I have converted this to a pdf to make it easier to download, but it means you won’t have the videos.   Just click on the link.

Now, one of our ‘fans’, Holly, has been making a lot of videos from the live streaming and clearly has a talent for this.   Here is her most recent offering

https://youtu.be/a6oM-p8bJuk – 30 Oct Highlights – You can also find her on Facebook and on her own Youtube channel, where she often adds music and other accessories.  Many others who follow the falcons do this as well ie have their own Youtube channels and upload videos to the Google Hangout which is linked to the chat.  the link to the hangout is https://hangouts.google.com/ then search for Orange CSU NSW Peregrine Falcons.

I have my own channel, too, but most of my videos are related to the research on the diet, so are recordings of prey items that I have not been able to identify.   If you have a nose for forensic detail, be my guest and have a go at identifying some!   they are all dated and named:  https://www.youtube.com/channel/UC9GrDUyVChN6kYroEWVKmeg.

Anyway, that’s enough from me.  Have a lovely weekend.





2 thoughts

  1. Whatever the reason for the size difference, it seems to be a feature common to the majority of birds of prey, which makes me wonder about the ones that DON’T have this size difference – why NOT? The feature must’ve evolved for a reason – why do some raptors have it and others not?

    Fingers crossed for successful fledges, whenever they may be!

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