Of the Cape Peninsula

Breeding

Pre-egg laying

If all goes well, the breeding cycle of a Black Sparrowhawk takes about six months. If something happens, like the loss of eggs and the birds lay a second clutch of eggs, the time spent breeding is much longer.

In the first stages the female becomes very lethargic and the male starts doing most of the hunting. He is rewarded for his provisioning by being allowed to mate with her. This also happens when he begins to build on the nest. With each addition of sticks to the nest his reward is the same. Females will also do some nest building, especially if the male is very young and hasn’t quite grasped the concept, but mostly she will reorder his placement of sticks to her satisfaction. The nest is lined with greenery (eucalyptus leaves, pine needles etc.) which is added almost throughout the nestling stage, although this seems to vary with the individual pairs.

It is thought that because nearly all the greenery is aromatic that it helps keep parasites like lice and mites at bay. It is also thought that the greenery on the nest might serve as a signal to other Black Sparrowhawks that the territory is already occupied.

Eggs

Eventually when the female is ready, she lays up to three eggs. She does most of the incubation but the male will sit on the eggs for a period each day to allow her to eat, bathe, preen and stretch her legs.

Chicks

The chicks hatch between 35 and 40 days.

At first they are little bundles of fluff, but this changes very quickly. At about 45 days from hatching they are busy climbing out of the nest and into the branches getting ready for their first flight.

Juveniles

Once the young birds take flight they then have to learn the skill of hunting for their living. For at least the next 3 months the adults will hunt with their offspring teaching them what they need to know to survive.

New Adults

By the time the youngsters reach a year old they are already beginning to grow their adult plumage. Surprisingly enough, if they can find a territory and attract a mate, they can begin to breed in their second year.

The bird on the left, who was ringed as a chick, was only 15 months old when she started nesting.

The bird on the right was so young when she started nesting that you can still see brown feathers on her chest.

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14 responses

  1. Marlene Hofmeyr

    It all looks quite amazing Ann, you have done a fantastic job, and it is really easy to follow. All your hard work has paid off and now we can indulge ourselves by feasting on your info and beautiful pictures!

    September 30, 2011 at 3:42 pm

  2. Congratulations on a great project Ann. Does your field of study include the northern suburbs of Cape Town (Tygerberg, Durbanville area)? I haven’t seen any ringed ones out here, but will look out for them.

    October 2, 2011 at 8:45 am

    • Ann

      Hi Mariana,

      I know that I have had ringed birds going as far afield as Durbanville, Somerset West and up towards Langebaan. Although I do not monitor Black Sparrowhawks in the northern suburbs I am still interesting in nest sights and ringed bird sightings.

      October 2, 2011 at 10:16 am

  3. Great blog with very interesting info… thanks so much for sharing. Looking forward to seeing more.

    October 2, 2011 at 10:05 am

  4. This looks great, well done to all involved.

    October 4, 2011 at 7:39 am

  5. Hi Ann

    I’ll let you know should I see ringed birds in this part of the woods.

    Regards
    M

    October 7, 2011 at 1:35 pm

  6. Paddy Walker

    Can’t believe how quickly the three fluff balls (okay well endowed with HUGE talons) in the Glen nest have sprouted feathers. They now strutt around the nest and in no time I expect to see the pigeon population of Camps Bay taking a dive. Maybe it’s the bling we put on their legs.

    I’m sure there was a Spar above Mowbray Golf course on Tuesday – must try and locate it’s nest. Any chance it could be in the pines on Rondebosch common?

    October 23, 2011 at 5:04 pm

    • Ann

      Hi Paddy,

      I don’t think the pine trees on Rondebosch Common are the sort that the Black Spars’ like, but who knows! With all the pines and Eucalyptuses coming down good trees for breeding in are in short supply.

      We did have bird trying to nest on Mowbray Golf Course in 2009 but the female was very nervous and got off the nest everytime a golfer came by. We weren’t surprised when the nest failed.

      I am very glad your three bundles of fluff are “full of it”. That is just the way Black Spars should behave.

      Happy monitoring,
      Ann

      October 23, 2011 at 6:57 pm

  7. Paddy

    Hi Ann
    The Glen pair are nest building. This is almost a year to the day (5th June 2011) that they started clearing the old nest. I have not seen the three 2011 chicks for some time. It would be fantastic if we could find someone who walks/runs on Signal Hill to keep a look out for these three sub adults as there are good clumps of pines and blue gums – especially on the N W side.

    June 9, 2012 at 11:42 am

  8. Hi Ann,
    This Blog is absolutely fantastic!!
    Can I ask you when start the breeding season on the Cape? and the courting periods?…
    Roberto

    May 27, 2013 at 1:46 pm

    • Ann

      Hi Roberto,
      Thanks for the compliment.
      The Black Sparrowhawks can start courting as early as February. Eggs can be laid from March to October. It is a very long breeding season. I am not sure of the courting periods. Our birds seem to spend most of the year hanging around their breeding territories.
      Cheers,
      Ann

      May 27, 2013 at 2:19 pm

  9. Paddy Walker

    Ann – the Glen pair are at it again. I’ve been checking on the nest and bits of greenery have been added during the last week then this evening I saw them mating. I have photographed the nest and will continue to do so over the next month to record progress. If they follow the previous two years breeding schedule she should start sitting mid August and the chics hatched around the third week of September. I will keep you up to date.
    Cheers

    Paddy

    May 28, 2013 at 4:40 pm

  10. Hardy Wilson

    Ann – wonderful site. Living in a high rise building in Durban we see Black Sparrowhawks using the buildings as ‘hides’ – in other words they sometimes appear to surprise the pigeons by flying around the buildings. Hardy

    April 7, 2016 at 5:48 pm

    • Ann

      That is most interesting! I would love to see the differences in how these birds act in different areas.

      April 7, 2016 at 6:08 pm

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