Hush Little Gull and eat your larvae. The Lake has left us a gift.
The Daily Bucket is a place where we post and exchange our observations about what is happening in the natural world. Birds, blooms, bugs & more - each note is a record that we can refer to in the future as we try to understand the patterns that are quietly unwinding around us.
July 27, 2013
We are down to our last week on this Lake Ontario beach but are still seeing and learning new bits about the lakeshore and dune settings. I've written of the big waves and the beach in general, and both diaries talk of stuff that washes ashore.
Today's tale is about something else found after 2 days of wind-driven turmoil, waves rolling over and over stirring up the lake bottom and pushing any detris to shore.
What are those Ring-billed Gulls eating out there?
They sure are busy pecking the sand about 3 or 4 times a second. And only in certain spots. Getting up to wander over, flapping my arms since that always gets a rise out of the gulls, I drive them off and bend over to look.
Actual size is 1/8" - your image may vary
It looks like some sort of insect larvae, thousands of them, washed up to the high water mark along our beach.
Zooming in on one of the photos I can see eyes or at least a head, antennae, no legs, and a segmented body.
From another NOAA website: Aquatic Insects of the Great Lakes
Nymphs and Larvae
Note on juvenile stages - Pupae are inactive stages (e.g., hard case, translucent case or cocoon). Larvae and nymphs are both active stages. Nymphs have rudimentary wings (or wing buds) and usually have jointed legs (usually 3 pair) similar to adults. Larvae lack rudimentary wings and usually lack legs or are limited to prolegs or projections (usually other than 3 pairs).
Ok. We know I'm bewildered by bugs but I'm guessing a larval stage that got churned out of the lake bed by the heavy surf. Your insights or other observations are welcome as we follow the orange beachgrass swaying in the wind for more beach oddities.
** Update - consensus opinion in comments says pupae and not larvae. I don't know enough to differentiate between the case of a pupa or the tube of a feeding midge larva
Munch munch munch - I'm still wondering how these gulls pick up this tiny larvae.
Peck with their beak and then tongue it? Collect a bunch and then swallow?
I do see them stop and tilt their head up at times.
There will be a 15 second video of the gulls posted in the comments. A humorous highlight is at the end when the lead gull looks up and squawks at my neighbors.
You can see the lines of larvae left by the waves.
Photos of these Ring-billed Gulls in flight are at a recent Dawn Chorus.
My guess is that these are some kind of midge.
There are four stages in the life cycle of chironomid midges. Eggs are laid on the surface of the water. Each gelatinous egg mass may contain up to 3,000 eggs depending on the species. Eggs sink to the bottom and hatch in several days to one week. After leaving the egg mass, larvae burrow into the mud or construct small tubes in which they live. Larvae enlarge their tubes as they grow. Suspended organic matter in the water and in the mud is used as food by the developing larvae
I found this neat pdf poster called
Lake Ontario Food Web.
"Chironomids/Oligochaetes. Larval insects and worms that live on the lake bottom. Feed on detritus. Species present are a good indicator of water quality."
Apparently by finding which species are living or dying, scientists can tell which pollutants are present in the water.
There's still insect larvae along the beach today. They were dead when they washed in, they are deader now. Don't see ants going after them, or the songbirds, just these gulls. When I looked at the larvae this morning, lots of midges were flying around and landing on me. Guess they were drawn to the dead bodies. More larvae washed in overnight, not as many this time, and the gulls were on to fresh pickings.
Something else will eat what is left of this larvae eventually:
Resident fauna on the beach are mostly arthropods:a variety of mites, beetles, flies, springtails, booklice, and small moths in the beach driftline on Lake Ontario sand beaches. These arthropods feed on washed-up plant, fish, mammal and bird detritus, fungi that grow on these materials, and each other.
Other things we saw
Bird poop caterpillar that the grandson spotted on a 3 foot cottonwood sapling at the edge of the beachgrass. I'll go out on a limb and guess that it is in this family of butterflies - (Admirals & Viceroy Limenitis)
It was there 2 days, not today, but I can see a few leaves that were stripped. Amazing to see it hang on to a leaf at the top of the sapling in a heavy breeze yesterday, flapping back and forth and over and under.
When I was investigating and tagging the plants on the beachfront lot, I found a Sand Dune Willow (salix cordata) - threatened species in NY, "only 6 to 20 occurrences" along this 20 mile range of beach dunes. I also spotted an orchid growing by our path down to the beach. Looks like a platanthera but it's odd that it would be in the dune and not in the wetland behind the dune.
Nearby, mixed in with what may be the rare & endangered Champlain Beachgrass is Canada Wild Rye lit up in all its glory by the setting sun.
More Great Lakes news I found when poking the web - another invasive species.
Bloody red shrimp is an invasive crustacean native to freshwater areas of the Black, Azov and Caspian seas in eastern Europe and western Asia. It has been found in all of the Great Lakes except Lake Superior. The shrimp was likely introduced and spread through the Great Lakes by ballast water from ocean-going ships.
Maybe the bloody red shrimp can eat the zebra mussels. They hail from the same seas.
Rain overnight, more on Sunday, that is a good thing. Good for the farmers with added benefit of keeping the hordes of invasive state park visitors to a minimum.
Update Sunday evening. The migrating shorebirds are arriving. A small flock of Semipalmated Plovers showed up - until all the beachgoers chased them off for the day. Great blog about these plovers, and here's a list from Ontario birders of southbound shorebirds. Very nicely done with bird descriptions and list of species and arrival times (adult and juvenile) that probably applies all across the Great Lakes. This checklist has links to lots of photos by family.
And The Daily Bucket is now open for your thoughts and observations...
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