Mystery Nest

Boy, spring hormones are kicking in with the local peregrine falcons. I was walking from the Mississippi National River & Recreation Headquarters to the visitor center in downtown St Paul when I heard a familiar "Per-chup per-chup per-chup." Sure enough, the local breeding peregrines were circling and diving towards each other. It didn't look like territory battle, but more display and pair bond reaffirmation.

While I was at headquarters, a co-worker showed me a nest that had been collected on one of the islands in our national park near the Twin Cities metro area.  She found it last fall and when she first described it to me, I couldn't figure out what was going on.  It was a nest that was covered with cotton, but had a perfectly round hole on top.  What could that be?  I finally got to see it today.

At first glance, I realized that it was two nests, one stacked on top of the other.  This could have been done for a couple of different reasons, maybe a bird decided to build on a nest from the previous year? Or, I wondered, if the bottom nest started as maybe a warbler nest and then a cowbird laid an egg and the warbler decided to start over with a new nest on top?  I asked my co-worker if I could pull them apart and she seemed hesitant, but then said it was okay.

I pried them slightly apart and low and behold, there were two eggs hidden in the bottom nest.  Now, here was the question, are these cowbird eggs or are these the original nest builder eggs?  For the non birders who read this blog, brown-headed cowbirds do not raise their own young, they are a parasitic birds and lay eggs in other species' nests.  Sometimes you will see a small bird like a yellow warbler feeding a brown bird twice its size.  That is a young cowbird that has been raised by unknowing birds.

I set one of the eggs on a ruler to measure it.  It looked to be about 5cm long.  I'm going to have to go home and look up the length of cowbird eggs vs warbler and sparrow eggs.  Based on where the nest was found, the most likely candidates for who made it would be song sparrow, yellow warbler, or common yellowthroat.  I'm not that great at nest id and I don't have any of my nest books with me.  Are these the nest builder's eggs or are these cowbird eggs?

We looked into the nest on top where there was some cotton looking material and a hole. At first I wondered if a mouse had covered up the top cup and used the double nest as a home, but then realized that the cotton looking layer was  mostly likely the lining for that nest, put in by the birds that built it.  The hole was probably made by a mouse or rodent, perhaps it could smell the eggs underneath and went to investigate? Perhaps there were originally more than two eggs and the mouse ate some (then decided they were old and nasty and not worth eating more).

So many questions left unanswered with this mystery nest, but quite a few stories in there as well.

Oh Hai, I Need My Bike

My friend (and beehive namesake) Kitty forwarded me an email from a Jon Freestone who has a robin nesting in an inconveneint spot.
Jon says: "The nest was built between a Saturday and a Wednesday (that is the day it was first noticed) It has been there for about two weeks now, figure I will leave it to just to see what happens."

I think we can get an idea of how often Jon uses this bike.

Odds and Ends

Gary Reuter has combined two of my passions: a bird house painted to look like a beehive! He used the wren house nest box plans from Woodworking for Wildlife and then just painted it to look like a hive.

Speaking of nesting, if you have noticed any nesting in your yard, consider participating in NestWatch--a new, free citizen science project developed by the Cornell Lab of Ornithology in collaboration with the Smithsonian Migratory Bird Center and funded by the National Science Foundation. Participants visit nests during spring and summer to collect simple information about location, habitat, species, number of eggs, and number of young in the nest. Then they submit their observations online.

“NestWatch introduces birding and simple methods of scientific inquiry to families, children, retired adults people of all ages and skills,” says project leader Tina Phillips. “It’s easy and fun. It helps people reconnect with nature in their own yard, nearby park, or nature preserve.”

In other words, this is easy for anyone of just about any ability and would especially be a great idea for kids to get an interest in nature.

While you're checking out the NestWatch site, don't forget to visit all the NestCams Cornell has going on too.

Also Karen Sowizral emailed me this photo she took of a two headed gull (insert sinister music here). I think it's two herring gulls (thanks Nicki ;) side by side, but it does look like something Godzilla might fight.

Non Restricted Heron Rookery

People were talking about Coon Rapids Dam on the Minnesota birding listservs. The great blue herons were returning to the rookery and there was a great horned owl using one of the nests. From my understanding, the owl has been there for the last few years--there's a plethora of nests for it to choose from but I've never made it over to see it. So I took a few minutes to go check out the rookery.

Some of the great blue herons were actively building nests, others were kind fluffed out as if they were too cold to want to deal with it. I couldn't tell right away which nest had the great horned owl. I followed the directions to try and see the fourth one from the right and all I saw were herons.

I systematically checked each nest. Heron...heron...heron...heron...oh hey:

You're not a heron! That's a little red-tailed hawk head! And the great blue herons don't seem to care. Granted, red-tails are a mighty hunter, but adult heron probably isn't high on their prey list. Young herons would be a possibility...but I wonder if red-tails do not like the fishy taste? The red-tail would have been in that nest before the herons arrived, so the herons are choosing to nest there despite the hawk. I wonder if the hawk has nested there before? I wonder if the hawk built its own nest or just refurbished an old heron nest?

I found some birders nearby and asked if they knew which nest had the great horned owl and they pointed to a cluster of heron nests away from the active clump that had no herons on them whatsoever. There in the center was a great horned owl. This cluster of nests was further back and I found it interesting that the herons nested next to the red-tail seemingly without any problems but gave plenty of space to the great horned--the owl would go for adult and young herons. I remember when I went to a rookery a few years ago and we found the night-heron remains with a big fat owl pellet in the middle. I wondered too if the early returning herons get the better nest spot farther away from the owls and if the later ones would be forced to take a nest next to the great horneds? Either way, the other active nests are in easy view of the great horns and I'm sure the owls will take a few nestlings from them. The red-tail is in easy view of the great horned...I wonder how that territory negotiation is going? The owl would have started nesting in January, the red-tail in early March, and now the herons. I wish I had more time to spend and watch the negotiations.

I also noted that almost every wire stabilizer had a staring next to it singing territory song. The holes that the wires go through are wide enough to easily fit a starling and the area on the inside must make a snug nest. Such enterprising birds.

New Year Nests and Resolutions

Non Birding Bill and I have been discussing our resolutions for the year. Some I started about a week ago--like the desire to lose 15 pounds (I'm tired of tight pants) so have been diligently monitoring my caloric intake and making a pointed effort to be active on a daily basis. My other resolution is to make more time for friends (we were at Mr. Neil's today, so there is a check off the list) and to become an apiarist (more on that in March).

What a perfect day to start off a new year! We had a lovely snow fall during the night and it was just cold enough to warrant a coat but you really didn't need gloves. The type of day you could easily spend the entire eight hours of daylight outside.

We finally cleaned out the wood duck box that was taken over by nesting house wrens. Check out the size of the nest we took out! It's huge, how could one tiny pair of wrens move so many sticks? This is the nest that had the saw-whet owl feather lining the nest cup. We've heard them and found feathers but have yet to see a live saw-whet owl on the property. I checked the bird banding lab and the oldest house wren documented is over 9 years old--wow! Must be the active life style.

As cool as it was to see how industrious a pair of wrens can be, I really hope we get wood ducks on the box this year.

I checked a grove of pines that I am positive will reveal a saw-whet to me one day and discovered a nest that I didn't notice over the summer. I have been to this spot countless times over the past year and never noticed this nest just 6 feet above ground.--that's only a foot above my head. No matter how in tune with nature I think I am, I always miss something (hmm, how many saw-whets have I passed??) How many times did I walk right underneath this little cup last spring and summer? I started doing a mental inventory of the birds at this spot in summer. Vesper sparrow? No, they nest on the ground. Eastern bluebird? No, cavity nester. Red-eyed vireo? No, pendulous nest, not a cup nest. Chipping sparrow? Hm, I would have to double check my Nests, Eggs, and Nestlings of North America.

Before I would go back and check the book, I wanted to photograph the nest to get all the detail I could for identification. I took a photo of the inside of the nest and found it full of snow.

While photographing the material on the sides, I noticed material that didn't fit all the grasses on the outside. There was a sticky matter and small stick looking shapes that zigged and zagged. It suddenly dawned on me: bones! The bones were part of a small bird's foot and toes and you could even see the tiny nails. Something had gone wrong with this nest.

I bent the branch down lower and blew my hot breath over it. After four blows, the snow melted and inside were the remains of what most likely was a chick. You can make out a scull towards the top center of the photo. The leg bones and foot extended up and over the outer side of the nest. I tried to take the pieces out, but they were completely frozen solid to the tightly woven nest. Even the sticky bodily fluids had become a tacky hard glue. There was no way to remove the fragile bones and I didn't want to trim the branch to take the nest.

So many questions: One chick left in pieces in the nest, what killed it? A snake would have swallowed them whole, as would a raccoon, mink, or weasel. Was it a blue jay, grackle, or woodpecker that came to eat the chicks and ripped them apart? Did the chick just die of some other cause like starvation or disease and then eventually a mouse found it and ate some of the dead carcass? Did the other chicks survive? What kind of nest was this?

Based on reading the nest book, it appears to be a chipping sparrow nest. The book says the nests are found 3 - 20 feet high, usually in a conifer and nest in a twig fork or among foliage. (check to all of that--the nest was 6 feet high in a pine on an outer fork) The book goes on to say that the cup is made up of dead grasses, weed stems, and rootlets; lined with finer grasses and hair. I see chipping sparrows there in warm weather so I'm going to go on a limb and call this a chipping sparrow nest--but I'm open to second opinions.

Alright, enough dead stuff. Let's end this entry with a great bird: a tufted titmouse! This wasn't my first bird of the year. That was a nuthatch that rouse me from my slumber early one, incessantly yanking outside the window. But I did get this little titmouse with the WingScapes Camera while we were at Neil's so it's my first photographed bird of the year. Whoot. I think that's a good omen for the year.