Cool birds

October is usually Harare’s hottest month with a maximum and minimum temperature averages of 29oC and 15oC respectively[1]. Surface water is very scarce so the garden birdbaths surprise you with their visitors.

Among the guests there are a few small birds of prey that are not “regulars” but that come sometimes: the Lizard Buzzard (Kaupifalco monogrammicus) and the Gabar goshawk (Miconisus gabar).

dscn9991-copy-2

The Lizard Buzzard standing in the water.

While at the water I noted that they both behaved in a similar fashion. Apart from drinking (the Gabar Goshawk also bathed), both species spent a long time (over thirty minutes two or three times a day on the days observed) standing on the water baths during the hot hours of the day, around midday.

dscn9903-copy-3-52-35-pm

The Gabar Goshawk standing in the bird bath, having had a bath.

Was it a coincidence or did they find relief by the freshness of the water in their legs?

I subsequently learnt that birds lower their temperatures through a variety of different mechanisms[2]. The bare skin on their legs and feet helps them to dissipate heat. Water birds stand in the water, presumably to enhance the cooling[3]. Some birds such as vultures and storks also use urohidrosis, the habit of urinating/defecating on their bare legs to cool down by evaporative cooling.

It seems likely that both birds were using the water of the bird baths to cool down their legs and feet and in this way, as the water birds, increasing the cooling effect of their bare skin.

Interestingly, since I wrote these observations[4], two more birds of prey had come and both species had stood with their feet in the water: an African cuckoo hawk, (Aviceda cuculoides) and what I believe to be an African Marsh Owl (Asio capensis)[5].

pict0226-copy-2

The more recent observation of the African Cuckoo Hawk (landing on the water) and the African March Owl below. These  4 pictures were taken with a Camera trap.

[1] World Weather Online 2016. Harare Monthly Climate Average, Zimbabwe. Accessed on 10/10/2016. http://www.worldweatheronline.com/harare-weatheraverages/mashonaland-east/zw.aspx

[2] Mayntz, M 2016. How Do Wild Birds Keep Cool in Summer? Accessed on 10/10/2016. http://birding.about.com/od/birdingbasics/a/howbirdskeepcool.htm

[3] Shriner, J 2012. 15 Unusual Ways Some Birds Beat the Heat. Accessed on 10/10/2016. http://www.birdinginformation.com/15-unusualways-some-birds-beat-the-heat/

[4] de Castro J. (2016). Feet bathing as a cooling down mechanism in two species of birds of prey. Biodiversity Observations 7.77: 1–2. URL: http://bo.adu.org.za/content.php?id=270. Published online: 22 October 2016

[5] Identification to be confirmed as the pictures of the owl have been taken with a camera trap late at night.

Advertisements

6 comments

  1. That very interesting, and something I didn’t know. And some great pictures.
    At one point we lived in Glen Lorne, on the edge of Harare. In the warm weather there often birds in the garden which you only saw in the bush, and not in the suburbs. I frequently saw some of the larger owls.

    1. Thank you. We have seen the spotted eagle owl early in 2013 and barn owls later. We are in Helensvale, north from Borrowdale. Thank you for reading the blog.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s