The plant is a black cherry Prunus serotina, a weedy little tree found throughout the New World. The leaf bears the mushroom-like galls of a tiny arachnid, the mite Eriophyes cerasicrumena. The animals are living inside the protuberance.
The white discoloration patterns on the leaf are feeding marks left by leafhoppers--small (but enormous compared to the mites) insects that puncture the leaf and feed on the fluid within.
Thanks always to Charley Eiseman, who expertly divines animals from the marks they make on plants. He rears galls to identify the adult insects--I think he has discovered new or locally unknown species doing this.
I discovered these feeding marks on the leaves of a quaking aspen (Populus tremuloides*) sapling recently. I figured a look through the old Eiseman and Charney book ought to settle it easily.
But it didn't. The kind of feeding--on the surface of the leaf, leaving the bottom surface somewhat intact--falls into the category of "skeletonization." In the second photo you can see the feeding is more fresh, and a line of droppings follows the path of feeding. I could find no specific reference to aspen leaf skeletonizers. I took the perhaps impolite next step of bugging Eiseman on facebook.
His alarmingly quick response was "Must be a beetle, but I don't know who it is exactly." followed by "Chrysomela was one thought I had--I think several species feed on poplars ... Some weevils leave similar patterns, but I'm not sure if any feed on poplar leaves. Various other chyrsomelids also feed on poplars."
So, until I find the beetle in the act, we'll have to leave it there. Thanks Charley!
* the -oides suffix means "looks like." So North American quaking aspen's scientific name means "Looks like European quaking aspen."
It's sometimes hard to appreciate exactly how damn small insects can be. They can be so small that space between the top surface and bottom surface of a LEAF can serve as habitat. In this case, a very insect larva chewed its way through the leaf of an aster, consuming the pulpy flesh and leaving a light colored trail.
Leaf-mining insects can come from any of 4 of the main insect orders--flies, moths, beetles, or sawflies. The host plant and the shape of the mine can be used to identify the insect in question. In this case, the miner is the larva of the fly Ophiomyia quinta*, which specializes on goldenrods and asters.
* "Ophiomyia" means "snake fly" probably a reference to the serpentine path of the leaf mine. Quinta means fifth. Dunno why it was named that.
No discussion of insect tracking can go by without mentioning Charley Eiseman and his amazing book Tracks & Sign of Insects and Other Invertebrates.
Lamb's quarters Chenopodium album* is a very common North American weed, and a close relative of spinach and quinoa. It is prized by the foraging community as an abundant and nutrient-dense green, found in suburban yards as well as urban sidewalk cracks.
The shape of the leaf and the tiny white-green flowers help identify it, but those red dots are the dead giveaway. Those are left by the nymphs of the Chenopodium leafhopper Norvellina chenopodii,** a small attractive insect that pierces the leaf with a tiny beak, sucking the juices of lamb's quarters.
* Chenopodium album literally means "little white goose foot."
** I couldn't find any reason for the name "Norvellina." It was probably named in honor of someone named Norvell. "Chenopodii" refers to the insect's host plant.
I canceled February's walk on account of we had more snow on the ground than any other time in history, and I didn't feel like walking through it more than I already was. We had a fair amount of melt in late March, and I was feeling good about seeing what creatures were out on the last Sunday of the month. Then on the Saturday before, it snowed again. In the Blue Hills, where the walk was planned, they got about 3 more inches. A friend and once-frequent Urban Nature Walker was going to be working at a maple sugar festival at Brookwood Farm in the Blue Hills, so that's where we went.
Above you can see the grounds of Houghton's Pond Recreation Area, complete with fresh blanket of snow and incongruent obsolete technology. We parked here and took a shuttle bus to the farm.
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This plastic liquor bottle was found at the base of an oak tree, in a staff-only section of the zoo, a good distance from the perimeter fence. Sometimes I'll find bottles near the fence--some drinker in the park decides to discard their container up and over. This one wasn't in throwing distance. My first thought was that some coworker was drinking bourbon on the clock; oh dear.
Then when I picked the bottle up, I noticed the cap had these markings on it. The cap was screwed on tightly, so some creature with very strong and sharp incisors had to chew through it to make this hole. It seems that this winter got to the wildlife as well as to the human population.
I'd basically given up on tracking this winter, since the snow is so deep. But here, in a public path in the zoo, a striped skunk left these beautiful marks in the fresh powder.
I was struggling to identify them, then I came across this set on top of the deep snowpack. That simple short shuffling stride is clearly a skunk.
These tracks suggest some drama. The parallel lines at the right were made by the wing feathers of a bird. The bird probably dropped out of our pine tree onto the snow, following the sound of a small mammal burrowing there. The footsteps at the left are confusing, but I think they belong to the bird as well. I suspect the bird (an owl) dropped onto the snow, missed its prey, then hopped a few steps before flying off. Before the blizzard, Alexis found a mallard wing in the same spot (which is also the same spot I found the owl pellet). Hope to see the animal responsible for all these signs soon!
This is the first owl pellet I've found in the yard! It's been flattened and misshapen by being out in the elements. It's composed of short gray hairs, which I suspect are mostly from voles. The only owls we hear calling are screech owls, so that's the most likely source, though it's a little on the large size for that.
I know I told you folks that I would try to keep you in the loop a little better, when it comes to Urban Nature Walks. Well, I'm going to keep to a schedule of every last Sunday of each month. So that means a week from tomorrow is the next one. This would be a lot simpler if you just joined the facebook group: /www.facebook.com/groups/
EDITED TO ADD: please let me know if you are signing up! I have to approve it, and I'm trying to avoid phishing schemes. Thanks, Chris!
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Despite the dry conditions, there was a bloom of reishi mushrooms coming from subterranean roots
Urban Nature Walk returns to the Riverway, on a quest to reach Ward's Pond, the spring that gives it water. I quickly got over doing an UNW on a Saturday (I have a mushroom class tomorrow) and met up with the group by the Longwood T stop. The first three to show up all brought gigantic cameras, so I will look forward to seeing their pictures, and linking you to them as well.
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