The Bashful Great Horned Owl at Robert's Ferry Bridge

There's a beautiful covered bridge on the Tuolumne River a few miles upstream from my town called the Robert's Ferry Bridge. It's not the original, which was damaged in the 1997 flood, but it is nicely designed complete with walkways on both sides. It's a nice spot for birdwatching, and in the spring it is a great spot to look for nests. Ospreys, Black Phoebes, and Cliff Swallows raise their young there, but the one I look forward to the most is the arrival of the Great Horned Owls (Bubo virginianus). They've used the same corner for a couple of years, and so I've been watching for their return.

I finally saw one of them today, and it clearly saw me, but I sure didn't see much! Were it not for the eye, I would have missed it entirely. I hope to see some babies in a few weeks.

Surprise After Surprise: Blue Grosbeak on the Tuolumne River

It's one of rarest and most precious of my local bird sightings: A Blue Grosbeak (Passerina caerulea). Until yesterday I had only seen three of them, all in one place, Ceres River Bluff Regional Park, over a period of just three days last summer. And someone else actually found the birds; I was following field directions just for the chance to see them. And that's it. Until yesterday, only two individuals had been sighted in Stanislaus County this entire year.

It's not hard to understand why. My county (Stanislaus) is relatively close the northern boundary of their normal range (although warming climate seems to be allowing them to expand their territory northward). The bird is a tropical migrant, so they are only around during the spring and summer.

So yesterday was the Global Big Day, where about 30,000 birders searched out and identified about two-thirds of all the bird species in the world (in case you wonder, that's around 6,700 out of 10,500 known species). I was out doing my part; Mrs. Geotripper and I set out into the prairies north and east of our town and identified birds at seven different locations (that's what we do for "recreation"). We found 47 species in total, but the biggest surprise was close to the end of the day. We were at the Robert's Ferry Bridge on the Tuolumne River in the Sierra Nevada foothills. We were checking on the Osprey and Great Horned Owl nests that we had seen several months back (Ospreys were there, the owl was not), when I saw a Bobcat wandering the bank of the river. I got one shot (below), and calmed down for a moment (I've only seen them in the wild three times). I then started counting birds again when a blue and chestnut colored bird flew through my field of view. The colors said "Western Bluebird", but I wanted to confirm, so I zoomed in on the bush, and my jaw dropped. It was a Blue Grosbeak!

The bird seemed to be having an argument with a Western Kingbird, and I got a shot of the two of them together. After a few moments it flew off westward (hopefully about 8 miles, so I can see it along the Tuolumne River Trail too).

Those were the two biggest surprises of a day that was filled with some neat surprises. It was a lot of fun contributing to citizen science efforts like the Global Big Day. The additional vigilance added to the number of Blue Grosbeak sightings. There are now 5 or 6 known individuals in the county.

The Problem of Scale and Zoom: What is That Up There?

I went out to Robert's Ferry Bridge on the Tuolumne River today to see if the Ospreys had returned to their platform on the south side of the river. It felt like time was passing without any Osprey sightings and I was worried whether they would be back at all. I was also curious if there were any birds nesting in the bridge structure, since I knew of several stick pile nests, but I couldn't tell if any birds were present.

It was really difficult to see the nests because they were in the eaves and framed by very bright skies. I had to depend on the camera to lighten up the darkness up in the eaves and I snapped a couple of shots. On the small screen of my camera the pictures seemed to show a bit of bird tail, and there was some kind of yellow thing, but I couldn't make out what it was, maybe part of the bridge superstructure, or a piece of plastic in the nest perhaps. It wasn't until I saw the pictures on my computer that I realized that my sense of scale was way off. It wasn't a bird tail at all! But at least I know who's on the nest ("who"...do you see what I did there? Do you get it?).

So, add a Great Horned Owl to the list of nesting birds in my area. Oh, and the Ospreys? They were there, both of them. They didn't seem too concerned about the herb garden growing in their nest. Now we watch and wait for all the babies to hatch!

Osprey Fledglings on the Tuolumne River and Anthropomorphizing.

We've been gone for 6 of the last 8 weeks, so we missed out on the childhood of the nestling Ospreys that are living along the Tuolumne River just upstream of our town. We last looked in on them in late April (story here), so we took a short excursion yesterday to see if the fledglings were still hanging out at their nests. They were, at least two of them, one at Roberts Ferry bridge, and one at Turlock Lake State Recreational Area. They looked healthy and active.

I know we're not really supposed to anthropomorphize wild animals, but looking at these scenes somehow brought back memories of teenagers... 

The "I can't handle listening to this kid whining so much" look...

The "you've destroyed my life forever" look...

The "I'm not speaking to you" look...

The "you WILL NOT talk about my child that way" look...(teachers get this one)

The "first driving lesson" look...

And...the response to the "birds and the bees talk".

I don't know, maybe there is something to anthropomorphizing after all.

An Inventory of Osprey's Nests on the Tuolumne and Merced Rivers

We can't resist the urge to check the Mother Lode Osprey nests each week when we get a chance to go outdoors. There are at least four of them along the lower reaches of the Tuolumne and Merced Rivers that we've found so far, and a fifth hidden in the forest near Table Mountain in the drainage of the Stanislaus River.

The birds themselves are spectacular to watch, if they are out and about. They have a huge wingspan, and are graceful flyers.

Activity at the nests is pretty muted, as we have yet to see any chicks. They may very well be there, but the nests are huge and deep. They are used year after year, and each year brings new sticks and other nest materials. The largest nests can be thirteen feet deep and six or seven feet wide. They have been encouraged to use artificial poles and platforms in our region.

There is a nest at the south end of Roberts Ferry Bridge on the Tuolumne River east of Waterford.

There is another nest on an old telephone pole almost hidden in the trees just south of the Merced River near McSwain Dam. One of the biggest nests is on a pole at the junction of Merced Falls Road and Hornitos Road at Merced Falls (below).

The nearest nest to us is on Lake Road just east of Turlock Lake State Recreation Area. The Ospreys there have both the reservoir and the Tuolumne River to utilize as a source of fish.

Under the category of "what did they ever do before telephone poles?", here is an Osprey nest in the top of a conifer tree near Table Mountain and Jamestown that I saw on a hike last week.

I wonder how often such nests collapse under their own weight?

We'll keep an eye out for young Ospreys and let you know when we get some pictures!