It's been a changeable week here on the Dyfi to say the least. The 30°C heatwave has gone, to be replaced by more 'normal' Welsh weather for July. Sunshine and showers and temperate 20°C.

Both the young chicks have changed too - they now look like little ospreys!

There's a Big Wind coming..

At over four weeks old both youngsters have now almost completely lost their white downy feathers and look resplendent in their growing adult feathers. The primary feathers are growing quickly, protruding out of each protective sheath. At this stage, the feathers are described as 'in-pin' and the young osprey will peck away and preen those sheaths until they crumble, ultimately exposing the feather underneath.

Glesni joined Monty in sharing fishing duties again last week after a hiatus of three weeks and for the first time she has caught a species other than mullet. Her eighth fish caught on the Dyfi this year was a sea trout. The fish count has been fairly high again this week, 25 in all to maintain two healthy growing little ospreys.

Weekly fish count - totals will probably decline over the coming weeks as the chicks' growth spurt curtails

Frustration Nest

Sometimes we hear people talk about ospreys building 'frustration nests'. These are birds starting to build an additional nest close to their primary nest. But why?

Frustration nests are usually associated with birds that have failed to breed in a particular year or birds that have finished breeding early. The Glaslyn male osprey is a classic example of this type of behaviour.  

Because both Glaslyn ospreys return to breed so early in the year (they usually have chicks by mid May!) they also, therefore, finish earlier. However, their biological clocks tell them that it's not time to return to Africa (or southern Europe, we don't know) yet. Problem is, the birds are still in 'breeding mode' in late July and August despite their offspring having fledged the nest weeks previously.

So a convenient interpretation for birds building supplementary 'frustration' nests (only a few sticks though usually) is this pent up urge the birds have to breed because they are still at their breeding site and breeding time of year. A classic 'displacement behaviour' where an animal's basic drive (in this case to breed) is frustrated owing to the fact that the chicks are well and truly grown up!

The Glaslyn male fetches a stick to add to his 'frustration' nest

So with all that cleared up then, what on earth is Monty doing in mid/end of July..

He's not failed to breed, he's not early (in fact, he's very late) and the chicks are only four and a bit weeks old. This camera pole was here last year and we saw no such behaviour then, but since around July 20th this year Monty has started to build himself a second nest - just feet away from his main nest.

How very, very bizarre!

Just when we think we're starting to understand these wonderful birds, they go and prove how utterly naive we all are. How very humbling. Please do suggest an explanation if you have one of what Monty is up to, because I have absolutely no idea!

Both chicks will be ringed next week - look out for a blog soon after.

UPDATE: August 4th:  We asked Roy Dennis what he thought Monty was doing, here's his response. Thanks Roy.

Some males do a lot of building as the chicks grow in the nest - it makes the nest flat and also more secure for the following year, but it is rare that nests have an obvious extra base just above them. The camera array top encourages the male to have the new nest at the most prominent place rather than down below the structure. He would prefer to use the highest site as it will have 360 degree vis and approach, if it was still there next spring he would use it.

This is what Monty's new nest looks like now, August 4th!!