From the Contact Station May 2023

Spring Soon Please

I know the Great Pacific Northwest has a reputation for rain, but seriously, aren’t we all ready for some prolonged sunshine? Ponds and lakes continue to be full. Have you noticed how many American Bitterns have been spotted along the edges of the road. They are used to wetlands, but having to swim through them may be pushing them to the edges where we are getting great views. You can see the Canada Geese sitting on the higher vegetation humps in Rest Lake. The wetlands nesters don’t like their eggs to be under water. I am wondering how much this will affect nesting success or cause a delay in nest starts.

On the Road Again:

The roads can be crowded at times. Maybe so much high water is pushing the wildlife up to dryer areas to move around more easily. Paying attention to the road ahead can be very rewarding for wildlife viewing. A hopping bunny, a dashing mink or a long-tailed weasel, a mama raccoon leading her kits, or a garter snake slithering across the sun warmed gravel. And there are the birds, lots of birds. Mixed flocks of sparrows on the roadsides are fun to sort through.  f you are lucky to enter the refuge early on a weekday when there is little or no people traffic, you might see an abundance of avian traffic. I once got in very early and found a Peregrine Falcon on the road having breakfast of a Green-winged Teal. I watched it for at least 15 minutes until a Red-tailed Hawk came along and tried to snatch the duck parts away, pushing off the falcon. I was able to ID the hapless waterfowl because the head was left as the falcon flew off with the bigger scraps. Yuck.

But why do the birds use the road. OK, to get to the other side.

Bad jokes aside, a nice puddle in a pothole can provide water to drink or to bathe in. Then there are easy pickings for seeds, bugs, reptiles, and grit. I watched a goose working a small hole in earnest a couple weeks ago. I was thinking if it continued for a while, we might have another pothole. Could that be why we have so many potholes? Excavator geese. No, wait, I am going too far here. But it was going after grit, which has an important function for birds.

Deep dive time – The Gizzard:

Most birds have two-chambered stomachs: anterior glandular part, or proventriculus, and posterior muscular part, or gizzard. Shapes and structures of avian stomachs differ more than any other internal organ, corresponding to the dietary habits of different species. Bird species that eat very easily digested foods such as soft-bodied insects, soft fruits, or nectar may have a very small and thin-walled gizzard. Lacking teeth to masticate food as we do, the gizzard provides this function. It is very thick and muscular in some species, such as ducks and doves. Ducks and geese eat a lot of less digestible fibrous foods. Some birds eat hard items such as seeds and nuts. Birds with thick gizzards frequently pick up grit—little stones, sand, and small shells. These items are collected in the gizzard. When food and digestive juices enter the gizzard from the proventriculus, the thick muscles and grit help pulverize the remaining food to extract the last bit of nutrients and to easily pass through the body. Some birds regurgitate pellets (owls) but that is a topic for another day.

Have you noticed our swallows sitting on the roads? They are all back now for the spring/summer season. Studies have shown that Tree Swallows particularly like mollusk shells for grit. Perhaps it is because they contain calcium and other minerals and may be tasty. There is much speculation that grit is also often collected by birds as an important mineral source. Interestingly, a recent study in Mexico looked at a variety of hummingbirds to see who, when and how much grit they collected. The results indicated grit is used mainly by female hummingbirds. The seasonal variation in the ingestion of grit by female individuals suggests that it can be used to meet mineral requirements related to breeding. Also, the use of grit was proportionally higher in juveniles vs adults, suggesting it is used for grinding arthropods during a period of fast development. Young hummingbirds are often fed spiders for their protein needs. Should I start looking for hummers on the road (the bird kind, not the car kind)? Humm, probably not. But somewhere and somehow, they may be looking for grit.

So, lots of reasons to go slow and watch the road for a variety of wildlife. Slow is also good to prevent casualties like the poor coot whose running skills were not good enough.

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Mosquitoes:

Fellow volunteer, Annette (Sundays in the Contact Station) and I took a long round on the River S auto tour mid-April.  We ran into Wade, the Clark County Mosquito Control (CCMC)Technician, and asked him all kinds of questions as he set up mosquito traps. They are monitoring weekly to assess the increase in adult mosquitoes over time. If you were down on the River S last July, you will remember the hordes. Wade recounted his experience last July when they started with a weekly count of 50 followed by 250 the next week then 550 the next week then 28,000 in one night! It was not your imagination.

We watched Wade set up a collection station a few yards off the path to the observation blind. The tripod has a bucket hanging from the top center. The black bucket contains CO₂ emitting dry ice and has small holes around its lower perimeter which leaks the gas into the air. The mosquitoes are attracted to the CO₂ thinking there is a blood-carrying animal nearby. There is a big cannister, placed below the bucket, with a fan that sucks the mosquitoes coming to the bucket into the canister. Mosquitoes captured in the canister are killed by more dry ice. The next day, Wade collects the bucket and takes it to the lab. There they count the mosquitoes and take a portion, up to 300, to identify to species.

There are twenty-three different species of mosquitoes in Washington State. The largest group is floodwater mosquitoes, or Aedes vexans, a species known for its residence in soil above the waterline of aquatic areas. They are not known to be disease carriers. CCMC looks for mosquito species that would spread disease, particularly West Nile virus. Once they’ve identified the suspect species, they test for West Nile virus to see if it is here in the area. The collections are done weekly until the numbers start to rise, at which time they may do collections four times a week or even daily. Mosquito abatement focuses on treating mosquito larvae with targeted biologic products as they hatch.

The females are the ones looking for blood meals to gain protein for their eggs. What Wade does to avoid being bitten is wear loose-fitting clothes of light colors with long sleeves and long pants. Mosquitoes are attracted to dark colors. He also uses DEET.  A 25% solution is effective.  He has learned that mosquitoes do have a slight attraction to DEET but they won’t land on a skin area covered with DEET.  But if you do your face and forget your neck, you can guess where they will bite! Cover all exposed skin, he advises. Once the mosquito lands, it is all a matter of your chemistry, whether they think you are tasty enough.

All mosquitoes like water because mosquito larvae and pupae live in water with little or no flow. This is why you find mosquitoes most often near areas such as marshes, ponds, and along riverbanks. Right now, it looks like we will have a lot of water again.

Wade told us an interesting story. He worked in the SE US doing mosquito monitoring. The way they determined when they needed to do abatement was by a field count. Two people would go into the field and one would open their shirt while the other counted the number of mosquitoes landing over three minutes. If they exceeded seven landings in that time, they would do treatment. Last July, while down on the Roth Unit, the closed section south of River S, Wade, faced with heavy concentrations of mosquitos, thought he would do a quick field count. He counted landings on his loose-fitting light pants.  When he got to 31 landings in less than a minute, he decided to retreat to the truck.

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What happened to the Blackberries?  Unless you haven’t been on the River S auto tour for maybe three weeks, you have probably noticed great swaths of vegetation are gone. The Refuge recently purchased a mini excavator and grinder head. The grinder head is very good at reaching into blackberry brambles especially where they are intermixed with existing trees. For years, volunteer groups and staff have been fighting the aggressive Himalayan Blackberries with sprays and hand cutting. This is not an easy process given the blackberries have huge thorns and are good at entangling pants legs and sleeves, while meting out a few scratches to arms and legs. The grinder pulverizes the blackberry canes to the ground, creating a kind of mulched area. We will have to see how this effort succeeds in holding back their spread. The areas may require spraying in the fall or a second grinding to keep them in control. The excavator grinder is a BIG help in an effort that would otherwise take months.

The work was accomplished now to avoid peak nesting season. The target was not the equally invasive reed canary grass that currently supports the Short-eared Owl roosting sights around the bottom of Rest Lake. Staff worked carefully in those areas, and the owls are still roosting there. Birders will miss the recently established Black Phoebe and the supporting cast of sparrows in the thicket under the trees between #12 and #13, east of Rest Lake. But, as they found that patch, they are sure to find another satisfying spot. Although there are no current plans to replant the areas with natives, we could hope that the native plants might find the opened areas more beneficial to their return. Meanwhile, the ability to see into and across the slough and other areas has vastly improved.

And lastly, Migration is happening.  The last couple weeks, Roger Windemuth has had over 70 species during is Wednesday bird count. This is the best time of year to get your biggest bird list in a day.

-Susan Setterberg, Contact Station Volunteer
images all by Susan Setterberg