With our Raptor Hospital reopened, we took the opportunity to invite Dr Hugh Hanmer from the British Trust for Ornithology to come and ring some of our patients who will be released over the next few weeks.
Teddy and Tilly the Tawny Owls
Teddy and Tilly the Tawny Owls were victims of our Avian Influenza lockdown. Both Owls were about ready for release when we received the news that we had to close our hospital. As a result of this, we were not allowed to release any birds either. We didn’t want them to lose any more fitness, so we hastily built a hack pen in a quiet area of the Sanctuary for them to move into. Although they have been provided with food, our trail cameras showed that they were also hunting for themselves, eating small rodents and insects which found themselves in the pen.
Normally, once birds go into a hack pen we do not disturb them apart from when feeding, and opening the hatch when the time comes for release. However, it was decided that ringing these two birds wouldn’t cause them any undue stress and would allow us to give them a final health check before letting them go.
With Hugh’s experience, we were able to determine that both are second year birds, and were a healthy weight. Tilly was considerably better muscled compared to Teddy, which suggests that she’s been doing most of the hunting in the pen!
Barn Kestrel
This male Kestrel’s release was also delayed due to Bird Flu. He was found in a barn with with a broken wing which we splinted to allow it to heal. This took a few weeks and he was ready for release when we were locked down. We put him in our largest aviary so that he had plenty of space to fly around, and once the restrictions were lifted, we arranged for his finder to collect him for release.
He was ringed the day before collection, which allowed Jess to assess the heal. Broken bones heal by rebuilding around the break, which for birds can often lead to bumps which would be detrimental to their survival (especially in such a streamlined bird as a Kestrel). Thankfully, Jess couldn’t feel any callouses near the break area so the Kestrel was given a ring before being returned to his barn.
Wonk the Little Owl
The young Little Owl has recovered remarkably well and will soon be returned to near where it was found so we took the opportunity to give it a ring aswell. Hugh confirmed that it is a juvenile from this year, and we admired the pink blush of the under wing plumage. This shows that there is still a blood supply as the feathers are still growing, but once fully grown, the pink will fade. Blood supply is still visible under UV light, and this is a useful tool for ageing Owls in the field, as older feathers won’t glow the same as new feathers.
Long-eared Owlet
Not many Long-eared Owls are ringed in the UK (in 2020 less than 200 were ringed, compared to over 6000 Barn Owls!), so Hugh wasn’t going to miss the opportunity to contribute towards the national dataset. Although still quite young, we think that this is a female, based on the plumage patterns that had already come through. Despite us having kept Long-eared Owls in our collection for years, this was a perfect example of wild and captive bird information being shared, as Jess hadn’t realised that this species is sexually dimorphic, meaning that males and females have different plumage. It is quite subtle in some species, and there is often an overlap but you learn something new everyday!
Tawny Owlets
When Hugh arrived, we had one Tawny Owlet for him to ring. But while he was with us, a second Owlet arrived. Both were ringed by Jess under Hugh’s supervision. The UK ringing scheme uses split rings made from Aluminium Alloy, Incoloy and Stainless Steel (depending on the size of the bird), which are fitted with specialist pliers. These rings are the equivalent to the birds wearing a bracelet or a watch and do not impact on the survival of the birds once released.
By ringing our Hospital birds before release, we are not only contributing towards the national database held by the BTO to monitor bird populations and health, but we can also assess whether our rehabilitation is successful. It is hoped that some of the Owls and Kestrels might be found breeding in a nestbox monitored by ourselves or other ringers in Suffolk, and the Long-eared Owl may well migrate once older, giving us an insight into where these birds get to!
For more information about the ringing scheme, please visit: https://www.bto.org/our-science/projects/ringing