I was south at the weekend, visiting the Red Squirrel Project on Anglesey, and as I drove from Manchester airport to North Wales it was the first beautiful sunny day for ages – as I looked into the skies I could see it was perfect weather for migrating ospreys. It was an excellent day for them to get going again after all the bad weather, which has been thrown at migrating birds this autumn. The good weather allowed the sun to shine on the honey buzzard, which has travelled south from Scotland and roosted last night just east of the M6 motorway south of Kendall. But alas there were no signals from Glen’s transmitter, but I will keep checking just in case it gets some sun and suddenly bursts back into life The Irish observers went and carefully checked his roost site but found nothing. It could be possible that he continued migrating and disappeared out over the Ocean, whether that was while trying to get back to the UK or straight on in a south or SSW direction we will never know, and there’s always a chance he is still there somewhere and the radio is not working at this time.

A few people have written to me with concerns that radio waves from the transmitters have affected their navigation. I am always very concerned that we do not cause damage to the birds we study. Of course, whenever we carry out such work there is a risk and we try very hard to keep this to as minimum a risk as possible and there must be a benefit to the species’ conservation. We and colleagues abroad have no evidence that the transmitters cause navigation errors. The radio transmits infrequently and only at certain periods over schedules of one to several days, up to ten. In good or average weather, the tracks of both adults and young show them migrating without any evidence that the transmitters are affecting their navigation. Ospreys, like other migrating birds, sometimes get lost or die when they run into storms and bad weather, especially in heavy rain and thick overcast. Then, whether they have a radio or not, they usually fly downwind and hope to make landfall, feed up and restart their migration; lucky ones even survive major storms. The transmitters show that migration can be very difficult, and also the range of difficulties that some migrant ospreys have to endure and how many fail to make it to Africa. It is important for us to realise the enormity of the natural risks of migration and why we must conserve them on the breeding grounds as well as possible.

On Friday, I checked Nimrod’s nest site on the first nice afternoon for ages; two of the young ospreys were still there, perched in trees a few hundred metres from the nest. They were very vigilant and gave alarm calls when they saw me. The female has been gone for some time now, and the oldest chick might have left. These chicks have been fed very well by Nimrod, and have had a good long post fledging period to build up strength and fitness before migration. I’m hoping they might have started migrating during the weekend’s good weather – none of the three young were ringed as it’s a very dangerous tree. As soon as the last chick leaves, Nimrod will be off and we now have a chance to watch the whole migration of an adult male osprey from his nest in Scotland to his winter quarters, for the first time using GPS accurate data. Here’s hoping he has good weather and a safe journey.