The mystery of the Red-capped robin-chats’ migrations.
Introduction.
Red-capped Robin-chat, a beautiful bird species that will leave you dazzled and happy. The orange underpants, throat and face, the greyish black wings, and the beady dark eyes bring the fine final touch to this already magnificent creature. Red-capped robin-chats are among the African tropical migratory birds.
A picture of a Red-capped robin-chat from one of our ringing sessions. This is young.
In June 2020, our science team took a special interest in these amazing birds. That was when they started fitting them with geolocators (a lightweight tracking device used to map migration routes and identify important staging areas), otherwise famously known as backpacks. The interest was in two afro-tropical migrants, the Red-capped robin-chat and the Mangrove Kingfishers which are found on the Kenya Coast from May to early November and outside these months no one knows where they go to.
The geolocators also provide some additional information like the altitude at which the bird is flying at a given time, the air pressure during the flight, and the time of flight, whether day or night.
Why the geolocators and why this species?
Robin-chats are among the many Afro-tropical migratory birds. They also happen to be among the few migratory species that pass through or visit Kenya during specific months of the year. Compared to the other migrants, we discovered that these Red-capped robin-chats have had a consistent pattern of coming back to our Mwamba plot. From our ringing database, we were able to understand their re-capture rate. We had very good records of birds we ringed previous years coming back to the same place (territory) the next year, which made it easier as you need to catch the bird again to retrieve (remove) the geolocator from it. Since their re-trap rate was so high there was a high chance of success in retrieving these geolocators for when they came back.
As conservationists, the biggest questions have been; where do they go after they leave Kenya and where do they come from? We also wanted to figure out the migration routes and patterns. We wanted to know if they indeed had migration patterns. And if they do, are these patterns specific and the same over the years, or are they random and change over the years?
A removed geolocator
How it is done.
We are grateful to the Swiss Ornithological Institute for choosing to partner with us on this four-year project. They provide the geolocators, fund the ringing process and later retrieve information from the geolocators. We receive 15 geolocators each year for the Red-capped robin-chats, fit them on the birds then wait to re-capture them the following year and retrieve the geolocators. So far, we have had 33.3% success in recovering the geolocators. The geolocators are then sent back to Swiss Ornithological Institute for data extraction. After the extraction, the raw data is sent to Raphael (an Associate researcher of A Rocha Kenya) who cleans, analyses, and explains it before sending the results back to us.
Removing the geolocator after the Robin chat is re-trapped the following year.
How we choose the birds to fit geolocators.
The deployment of the geolocators usually starts in June, since that is when most of these birds begin to settle in. The first thing we highly consider is the age of the bird as we would prioritize putting geolocators on mature birds, and limit putting them on your birds. Secondly, the re-traps (those with rings from the previous years) are preferred, especially during the early days of this migratory season. This is because, we can be able to trust that this is part of their consistent migratory corridor/ route or destinations. The chances of re-trapping it again are high. Those without rings, however, are least considered at this stage, as they are still perceived to be wandering around looking for territory of their own
From mid-July (later into the season), if we haven’t managed to deploy the 15 geolocators, we start to consider mature robin-chats without rings on (those that aren’t re-traps). This is because by mid-season, birds usually have identified their territories. So even if the bird doesn’t have a ring on from the previous years but is still around by mid-season, then chances are it has identified this as its non-breeding territory for the next couple of months and years. In addition, it may just be a bird that has been around all along but just didn’t find its way into the nets.
Fitting the bird with a new geolocator.
The outcome
Our initial findings from the retrieved data suggest that the Robin chats fly down to Mozambique after they leave Kenya. It has also been discovered that they generally fly at different altitudes when they are going to and when they are coming from the breeding grounds. We are really looking forward to what more we will be able to learn from these beautiful birds. Stay tuned. You can find additional updates we have been making on our social media platforms over the years from 2020 when we began. Check it here, here, here, and here. You can also get another detailed report about this in this first article we published earlier on here.
A Robin-chat with a fitted geolocator on its back