Introduction

The juveniles in both the Boulders and Owosso Osprey nests are growing and occasionally flapping their wings, and the Boulders’ juveniles are beginning to vigorously exercise and hover.

The large image above at the top shows an unknown Osprey flying with a fish it captured upstream from the Greenway Bridge. The photo immediately above captures a moment as the Osprey shook off the water from the dive. This was probably a male from the nest near I-105 near the exit to Delta Highway, as it flew in that direction with the fish.

Owosso Nest

The Owosso juvenile has grown and occasionally stretches its wings, but we haven’t seen it hovering yet.

The Owosso Ospreys continue adding branches to their nest, as evident in the three photos photos above. The BirdNote podcast episode for August 10, 2023 describes this Ospreys behavior of adding to and ’tinkering’ with the nest.

The Owosso juvenile is now frequently sitting up, as in this photo from the far side of the river, next to the adult female.

The Owosso adult female frequently leaves the juvenile alone in the nest for short periods.

The Owosso adult male Osprey is rarely in the nest and sometimes perched in a tall snag nearby when not off fishing.

We watched a male Osprey struggling with a large fish (probably a largescale sucker) on a gravel bar opposite the Owosso nest for an hour on August 10. Our initial assumption was that it was the Owosso male, but the female flew over and must have seen the action but made no effort to land and join the feast. We are unsure if this was the Owosso male or another Osprey, as it was still on the gravel bar eating when we left.

In June 2020, we saw the Boulders male struggling with a large fish near the nest, and he called to the larger female who helped to carry it off—here is the link to that article.

Boulders Osprey Nest

The Boulders adult female continues to feed the runt of her family of three, much to my relief, as in this photo on July 30. I also observed her feeding the runt on August 8.

The size difference between the runt and its older siblings remains stark. This is the most significant size difference I have observed in Osprey siblings at the Boulders nest in the four seasons I have been watching. Fortunately, I have seen no sign of aggressiveness by the older siblings toward the runt.

When food is limited, younger siblings often starve. With regular, abundant food, no apparent aggression or dominance, and young often feed side by side, female feeding siblings equally.

Bierregaard, R. O., A. F. Poole, M. S. Martell, P. Pyle, and M. A. Patten (2020). Osprey (Pandion haliaetus), version 1.0. In Birds of the World (P. G. Rodewald, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.osprey.01

The Boulders male continues bringing fish to the nest which suggests there isn’t a shortage of fish, and probably explains why we haven’t seen aggressiveness by the older siblings.

The Boulders’ older juveniles have begun to hover a little at the nest, and to my surprise, the runt is also exercising its wings.

Over the River

On August 9, we heard three Ospreys calling loudly above the Willamette River and saw two flying separately. It could have been the males from three nearby nests, Boulders, Owosso, and perhaps the one near I-105. I captured a photo of one of them as it flew.

This temporary gathering of three or more Ospreys is something we have witnessed every summer, and we always wonder about the connections, if any, between the individuals—are they relatives?