Saw a Paper Wasp “Aggregate” and a Bullock’s Oriole Nest on Saturday

I got up at about 6:15 on Saturday and was out the door with the dog by 6:30.  We went over to the Sacramento National Wildlife Refuge.  Like the Cosumnes Preserve, it’s really early in the migrating bird season, so I wasn’t expecting a lot.  I just wanted to see how their wetlands were shaping up.

I was surprised to find a thick fog bank hanging over Woodland on I5, but it lifted almost as soon as I left Yolo County.  Hah!

At the refuge, more than half of their wetlands area is still dry.  There were small flocks of Pintails and Northern Shovelers in the deeper ponds, and lots of Red-Winged Blackbirds, but most of the water birds I saw there were Coots, White Fronted Geese and Snow Geese.  The flocks were pretty distant from the car, too – because the areas closest to the auto tour road are still dry – which makes photographing with me equipment kind of difficult.  Sightings will get better as the season progresses, but right now it’s kind of frustrating.  I did come across a few hawks, including a Northern Harrier, but they were in flight or hidden in the trees where it was difficult to get any clear photos of them.  The only way I recognized the Harrier was by it white rump patch.

By the small outhouse that’s about halfway through the driving tour, I saw clusters of Paper Wasps.  They were somehow clinging to a vertical metal sign, but were all bunched up in a pile.  Others were grouped side-by-side along the back of the sign.  I’d never seen this behavior before, so I took a lot of photos and looked it up on-line.  The behavior is called “aggregating” and it’s apparently a common thing for late-hatched female Paper Wasps to do in the fall and winter.  What I was seeing on the sign were “pre-hibernation” aggregates.  As the weather gets colder, these wasps will find a place that’s more secure and sheltered (like in a crevice or under the bark of a tree), called a “hibernaculum” where they’ll stay through the winter.  If they survive, they’ll emerge again in the spring to breed. Interesting!  I learn something new all the time.

Oh, and I also came across a Bullock’s Oriole nest hanging in a tree.  I’d never seen one of them before.  It’s a hanging nest with “handles” on the side and open at the top.  According to Cornell’s “All About Birds” website: “Hanging nest, neatly woven of hair (especially horsehair), twine, fibers, grasses, and wool, lined with cottonwood or willow cotton, wool, or feathers. Placed in isolated trees, at edges of woodlands, along watercourses, in shelterbelts, and in urban parks, often near water.”  Cool!  Now I know what to look for…

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When I do the auto tour, I keep the car windows open so I don’t have to photograph through the tinted glass, but as a result of that, when I’m done with the tour, I to shoo out all of the midges that fly into the car and cling to the ceiling.  Eew!