Don't ospreys read the textbooks?

Those of you that have visited us, read previous blogs, or followed our Facebook page will know that the scripted order of osprey migration goes as follows:

Female first
Chicks; eldest to youngest
Male last

In previous years we have seen some exceptions to the rules.

In 2011 we watched on as Monty left Leri and Dulas behind, hanging around the nest until hunger ultimately forced them to migrate; the tough love approach worked.

In 2015 we know that eldest chick, Merin, left 2 hours and 2 minutes before Glesni, and also saw Brenig, the youngest chick, migrate two days before his older sister, Celyn. Clearly these youngsters hadn’t been reading the textbooks!

This morning we have seen Menai and Eitha. Aeron, however, is still nowhere to be seen.

One of the final photos of Aeron

Having meticulously checked through recordings, we know that he has not returned to the nest since he left at 08:23 on Sunday morning. We were somewhat dubious to call it, however, knowing that fledglings often start to roam further from the nest prior to their departure; Menai was absent for almost 9 hours on Saturday, returning only when hunger got the better of her.

Over 48 hours have now passed since we saw Aeron, and we are almost certain he has left for good.

Aeron taking flight as his sisters look on

Many people have expressed their concerns given that he left before Glesni; assuming he left too early, before he was ready. The graph below shows the ages of all previous Dyfi chicks at the point we last saw them. Aeron was younger than average for the males, but over two days older than Cerist, our current record holder. 

Though Aeron is the youngest male chick to migrate, he only beat the record set by Gwynant in 2014 by 16 minutes!

Attention now turns to the girls. We haven’t seen Glesni since 17:20 last night (14th August), which is unusual for her and definitely raises our suspicions that she has started her long journey south.

With the exception of Clarach and Cerist in 2013, all previous female chicks have waited until they were at least 84 days old. Today, Menai and Eitha turned 85 and 81 days old, and have both been seen on more than one occasion. 

The two sisters remain on the Dyfi, still being fed by Monty

The weather is looking slightly more unsettled towards the end of the week, with stronger winds and more rain forecast. Maybe this prompted Glesni to leave, using age and experience to plan her departure?

Given the four-day age gap between the two remaining girls, Menai will probably be the next to go, or will she also defy the osprey 'textbooks'?

Time, as always, will tell.