How to Watch Kestrels
Kestrels are typical raptors that have the ability to sit for long periods, seemingly doing nothing, but can easily cover large distances quickly disappearing from sight. The outline below aims to give some tips on where to find kestrels and how to interpret their behaviour so you can position yourself to maximize your time watching them.
When to watch kestrels
The easiest time to watch kestrels is at their nest sites (cliffs, trees or buildings) during the breeding season. This is because they are forced to return to a particular spot (the nest site) on a regular basis. Finding kestrels during other times of the year can be more difficult, but knowledge of their habits and local conditions can help. Kestrels often hunt by hovering, and this is aided by hoving into the wind on slopes where there is natural lift. Thus, kestrels can often be found hunting on slopes facing the wind. Note that if the wind gets too strong and they have to start flapping hard to maintain their position, the advantage of hovering on the slope is lost and they then rather sit in some position out of the wind.
The morning or late afternoon is the best time of day to watch kestrels. During the late morning and early afternoon they tend to sit quietly making them more difficult to find. I try to get to a roost site (often near their nest site) around first light. Typically Rock Kestrels like to warm up a little before getting going, so at first light try to find a nice sunny spot in which they can preen. Once you have spotted the kestrel, you can then try to keep them in sight for as long as possible.
How long should I watch kestrels
Obviously, one can watch for as little or as much as you like. However, to gather a meaningful picture of what is going on, my criteria are:
- Try to visit you kestrel site at last once a month, and twice a month during the breeding season (September to December in South Africa)
- Try to spend at least 3 hours in the area or at the nest site. Males can stay away from the nest site for several hours when the female is incubating. If you stay for only a short period, you may think the kestrels aren't there, while they are actually sitting on eggs!
What should I take along
You can take what you like, but when I go looking for kestrels for a morning, I typically take:
- Binoculars and notebook - if I forget one of these, I don't even bother
- Telescope on a tripod - watching kestrels often happens over a long distance so the telescope makes all the difference. I use a 20X wide angle and 20-60X zoom eye pieces, depending on whether I need to see detail, or just watch a cliff from a distance
- GPS - helps me pinpoint where I was on my computer when I get home. It is also useful in measuring distances from other nest sites or sightings.
- Flask of coffee and a pack of biscuits - just to help through the long hours
- Extra clothing - the weather can change quickly on the Peninsula, so I carry something waterproof and warm
General behaviour
Kestrels can be seen doing the following behaviours at any time of the year:
- Hovering: The kestrel hangs motionless in the air, scanning the area below for prey. Depending on the amount of wind and lift, the kestrel may or may not flap. After a short while, the kestrel may move to a new position and hover again. From this position, the kestrel can dive down to catch food.
- Perch hunting: The kestrel perches for long periods, scanning the ground around it for prey.
- Soaring: When the kestrel wants to move a longer distance, it often circles up high in the sky before moving off. Soaring is also often recorded during the midday period, when the kestrels take a break from hunting.
- Zig-zag display: This display can been seen through out the year but is seen more often in the breeding season. It is often in response to another intruder kestrel in the territory. I think both sexes peform this display but it is done most often by the male. The kestrel will fly high above the territory and will then fly fast with fast shallow wing beats, flying from one side to the next in a zig-zag patter.
Behaviour in the early breeding season
Kestrels start getting ready to breed in spring. On the Cape Peninsula, the pair starts spending more time at the nest cliff from around August. During this time, the male will be trying to get his female interested in a nest site, will be chasing other kestrels and raptors away from the cliff and will start to feed his female.
Female Rock Kestrel on a potential nest site early in the season.
Typical behaviour
- Nest site selection: The male will fly to his selected spot and make "chip" calls, trying to entice the female into the nest. He will stay in this site for a couple of minutes, before flying out again.
- V-wing display: This display is often associated with the nest site they will use. The male will fly into his selected spot with his wing held up above his body in a V-shape.
- Nest cliff defence: One or both kestrels dive bomb any other kestrel, raptor or raven. Depending on the intensity, they may give their alarm call, a high pitched "kik-kik-kik" call.
- Feeding the female: The male arrives with food and gives his trilling call. If he doesn't take the food to the female, she will fly to him and take the food. The male and female may copulate after she has finished eating and he may fly to a potential nest site and make some "chip" calls.
Behaviour during egg laying and incubation
In the last two weeks before incubation, the female spends most of the time at the nest site and is fed almost exclusively by the male. She also starts to spend more time sitting on the nest, even if there aren't eggs yet. Eggs are most often laid in the morning two days apart. The female normally starts incubating after the third egg. When the male brings food once incubation has started, he will sometimes sit on the eggs while the female eats. The length of sitting can depend on the individual as some males seem sit on the eggs longer than others.
Rock Kestrel nest with clutch of eggs
Typical behaviour
- Egg laying lethargy: The female will sit near the nest site, sometimes with the feathers puffed up a little. She will spend most of her time dozing or watching the activity around her.
- Food passing: The male arrives with food, giving his trilling call. If the female is not on the nest, she will fly to the male and take the food. The male and female may copulate after she has finished the food. During incubation, the female will be sitting on the nest. Here the male calls her with his trilling call until she comes out. Then he will give her the food and then fly into the nest to incubate while she eats. If the female does not come out of the nest, the male may take the food into the nest, or will cache it and then fly off again. Once the female has finished eating, she may return straight back to the nest, or fly off for a break, possibly to preen or dust bathe somewhere else. If the female is away for a long time, the male may get impatient and repeatedly get up off the nest and call and in some cases, may even leave the nest unattended.
Behaviour during the nestling phase
The main change in behaviour during this stage is that they now regularly take food into the nest. In the first two weeks, the female will do all the feeding and the male does the providing of food. After that, the female may also partake in hunting for food. However, the primary job of the female during this time is to protect the nest from any potential predators.
Female Rock Kestrel bringing food to newly hatched chicks (photo by Braam van Zyl)
Typical behaviour
- Food provisioning: In the early stages, the male will pass food to the female as in the incubation period and the female will then take this food into the nest. Later on, the male may also drop off food at the nest ledge, as the nestlings get bigger and are able to deal with the food themselves.
- Nest defence: One or both kestrels dive bomb any potential predator in the air or on the ground. They give their alarm call, a high pitched "kik-kik-kik" call.
Behaviour during the fledgling phase
On the day that kestrel chicks leave the nest, they don't fly well and often spend a bit of time on the ground or other accessible places. This is made worse if the brood is big and there is a large age difference in the first and last chicks. Then the first chick leaves the nest but the last is still a couple of days from being ready, but tries to leave the nest early anyway. In South Africa, the chicks spend time with their parents for about 1 month.
Two recently fledged Rock Kestrel chicks hanging around on their natal cliff.
Typical behaviour
- Chicks out the nest: Chicks first hang around together close to the nest. They will make unstable flights around the area but as they become more confident, will fly further and will become very noisy, making a begging screaming call when the adult arrives at the cliff. Much of their activity is in the morning and afternoon as they have a doze around midday. Often, if they are away from the nest cliff, they will return to the nest cliff to have their midday snooze.
Counting Kestrels
Kestrel counting is another activity that especially the people associated with the Migrating Kestrel Project have to do. These kestrels spend their wintering period in Southern Africa so typical behaviour seen is mostly related to hunting, plumage maintenance and roosting. The following resources may be useful if you need to count kestrel flocks: