Eclipse Light and Temperatures

 As I showed in the companion post about my experiences during the 2024 total solar eclipse, I made an Arduino-based light and temperature sensor to record the changes during the eclipse. The goal was to record at a regular interval from the start to the end of the eclipse. The set-up involves four main components beyond the Arduino: a photoresistor, a digital temperature sensor, a way to write data to an SD card, and a clock to track the time of day. While the Arduino has some built-in timing capabilities,  they always restart at 0 when the power is turned on. A real-time clock has a watch battery so it can keep the time even when turned off.

I have a data recording shield from Adafruit that includes the SD card system and the clock all on one board that fits on top of the Arduino board. That provided two of the components. Light and temperature sensors are pretty common. I settled on using a photoresistor that came with my starter kit and a digital temperature sensor that was part of a suite of sensors. 

For the photoresistor, I needed to build a voltage divider so I could measure the change in resistance. Finding the right value for the fixed resistor in the divider can be a challenge and one I largely failed at in the end as you'll see. Measuring the light is one of the earliest lessons in the starter kit so I just copied that code over. Likewise, the temperature sensor has a simple tutorial program that I copied in. Below is the breadboard layout with the data logging shield hiding an Arduino.

Breadboard view of the sensors 

The clock needs to be set whenever a new battery is put in or if it has drifted over time. When I was doing testing of the recorder, I noticed that during some tests, I was getting default times instead of the real time. But other times, it worked fine. I was focused on getting the rest of the system working so I hadn't focused on the time but it was annoying. It was also messing up which file I wrote to as the filename was constructed from the date. Obviously something was wrong with the set-up or the code. It wasn't making sense that it sometimes worked and sometimes didn't. I finally thought to test the battery and the voltage was low so it was about dead. When I was testing and I noticed the wrong time, I would reprogram it but then leave everything plugged in to the computer while doing testing. Since the clock was still powered, it held the time fine. But if I took it off computer power for long, the battery would fail and the clock would reset. A new battery quickly fixed that. 

I settled on recording data every five seconds. Each time through the loop, I read the light and temperature values, then I could write them out to the SD card along with the time. I didn't need precise timing for this so I used the built-in delay function instead of checking the time from the clock. I was a little concerned about generating too much data but that wasn't a valid concern. In the end, the file was only 141 KB. And that included some additional debugging fields for each write.

I took the working system outside one sunny day for an extended test. When I looked at the data after about an hour I noticed the temperature climbed pretty steadily getting up to near 100 degrees F on a day with weather only in the low 70's. I suspected the sensor was heating up in the direct sunlight and that was giving the high readings. I needed a way to shade the sensor while still letting air flow around it. A box would trap air and be slow to respond to temperature changes. I also needed to have light reach the photoresistor. I tried an open-weave basket over part of the breadboard but that was hard to cover over the temperature sensor. So I ran the photoresistor wires through the open weave so the light sensor was on top while the basket shaded the temperature sensor. But that turned out to be awkward to connect and disconnect the wires for transport. I settle on an index card folded over like a tent to shade the temperature sensor but leaving the rest of the set up exposed to the sun. That worked OK but might have contributed to the fluctuating temperatures recorded. 

The day of the event I set the board out on a side table and put the tent cover on it and let it start recording. All went to plan except for the light calibration. I had played around with the fixed resistor in the voltage divider to try and make sure I covered a good range. Apparently a flashlight is much dimmer than in the sun so my middle point for calibration was much too dim and throughout most of the partial eclipse I was maxing out the sensor. Only right at totality could you see the light drop off. That's a bummer but OK considering this was about my fourth priority on the day. 

Below is the full event's data. You can see the light is flat for all except the shortest amount of times as totality hits. The temperature rises as the afternoon progresses and then starts dropping off as more and more of the sun is covered. 

In total, it was a fun project even if I ended up deciding to do it late so it was a bit rushed and not as well tested as needed.

2024 Solar Eclipse

This spring we were able to experience our first, but hopefully not last, total solar eclipse. Even having read lots about eclipse experiences, it greatly exceeded our expectations. 

We were lucky that my parents live in the path of totality, so we made early reservations to stay near them. After checking out the options and the eclipse coverage, we all decided that watching from their front yard was our best option. No traffic to deal with, plenty of access to food and drinks, cover if the weather turned on us. Plus we could have more comfortable chairs.

The weather forecast the days leading up to the eclipse weren't great with predictions of overcast skies ranging from 60-80% likely. But things started to turn for the better in the last few days. It was cloudy on the drive up and even a bit a rain as we arrived Sunday. However, Monday, the day of the big event, turned out to be a beautiful day. There were a few sparse clouds in the morning but they cleared by early afternoon and we had a gorgeous, sunny day. 

All the optics are ready and protected

The eclipse started around 2:00 pm so shortly after lunch we started to set up. I had my camera with a solar filter set up on one tripod. Sharon set up our birding scope on the other, also with a filter. We hadn't originally planned to use the scope but I didn't consider the size of the lens hood for my camera when I first bought a solar filter and just went off the screw-on filter size for the lens. That filter ended up being too small to fit, so I had to buy a bigger size. The first, smaller, one did fit the scope, so now we could watch up-close in real-time and get photographs. We also had glasses for everyone and laid a white sheet out on the ground. 

Some more friends joined us

At 1:53 the partial eclipse started with just the slightest sliver of the sun disappearing. As the next hour progressed we kept seeing more and more of the sun disappear behind the moon. For most of that time, the effects were hard to see if you weren't looking at the sun. 

Through the scope we could easily make out a couple of sunspots and use those to help track the progress of the moon. We also used a colander to project little sun shapes on the sidewalk. A great way to see the eclipse if you don't have your solar protection with you. 

Using a colander to project the partial eclipse

Somewhere around 90% coverage, we could start to notice changes in the quality of the light. It was detectably dimmer; kind of like at dusk but since the sun was still high above, it didn't quite seem like dusk. Sharon pointed out that it was dim but still a single point of light so we were casting sharp shadows. Not something you see at dusk or overcast days. Very quickly the light kept fading and we could see the automatic garage lights turning on around the neighborhood. 

In the final seconds before totality we could see the light quickly fading. On the sheet and the sidewalk we saw shadow waves as the dim light refracted through the atmosphere. We had read about this, hence the seemingly random sheet on the ground, but it was nothing like we imagined. Almost spooky in the dim light. 

We all removed our glasses as the last of the sun went behind the moon. Along the visible horizon we could see light, looking out beyond the extent of the moon's shadow to where it was still day. Seeing the shadow move over us and then being able to see the sun's corona was an amazing experience that is hard to put into words. 

Although totality lasted more than three minutes for us, it went by quickly. I tried firing off a lot of photographs but at first I had failed to remove the solar filter so all I got was blackness. Once I realized that, I did take several more but didn't do the bracketing that I had wanted to do. So the images turned out fine but I didn't get the range of corona that I was hoping for. 

Totality

In the video below, you can see the shadow approaching as things get dark, the lights turn on, and then hear us react to totality. It ends with the sunlight coming back up. Again, I didn't quite capture the images I was hoping for. This camera did automatic ISO adjustment. You can kind of see it getting noisier as it darken but not nearly the change in light that we actually experienced.

About 30-40 seconds before totality ends, we felt the winds pick up. You can hear that on the video too. It was a cool wind blowing in from the northeast, the direction the shadow was moving. During totality, we could feel the temperature drop. And as totality ended, we again saw the shadow bands. 

I also wanted to capture the changing temperature and light levels throughout the day. I built a simple data collector using an Arduino board, and digital temperature sensor and a photoresistor. I'll write more about how I built that in a companion post. Again, I didn't do a great job calibrating the photoresistor so it was maxed out for most of the time but you can definitely see the sudden drop in light levels and the accompanying temperature drop.

Temperature (red) and light level (normalized, blue) during eclipse

We stayed out and watched the sun slowly come back over the next hour. It was almost like the previous hour but in reverse. Except there was less anticipation as we had already experienced the amazing changes of totality.

In some birding circles it is common to celebrate seeing a new species of bird with a slice of pie. We built on that idea and had celebratory eclipse brownies that evening.

Eclipse Brownie

We are looking forward to finding a way to see another one. And if you haven't experienced one, it truly is on a different level than a partial eclipse.

Kayaking to Metompkin Island

 For the long Fourth of July weekend my wife and I wanted to do a short day trip. We had the Monday in-between off and one of our favorite kayak guides, Burnham Guides, had a trip to the barrier islands of Eastern Virginia. This is a great stretch of islands from Assateague in the north, home of the famous ponies, to Fisherman's island at the southern tip where the Chesapeake Bay Bridge Tunnel reaches land again. Thera are about 14 large ones protecting the Virginia Eastern Shore. Going with a guide relieved us of dealing with a lot of the logistics, in particular, finding a safe place to paddle that wouldn't be too crowded on the holiday weekend, and not worrying about getting lost in the maze of marsh creeks.

For this trip our group of 8 plus guide headed from Gargatha Landing out to Metompkin Island. This would be a six-hour trip with plenty of time for lunch and exploring Metompkin and swimming in the sea. It was a great day to be on the water paddling and, apparently, a good day for fishing. At the boat launch there were several people fishing from both the shoreline and in small craft in the creek. There was another group surf fishing out on Metompkin. Besides them, we only passed two other boats including one just as we were coming ashore at the end. Neither boat was very loud so it was a very peaceful trip. 

Route we took from Gargatha Landing to Metompkin Island

As each of us launched our boats, we crossed the creek and waited, giving time for everyone to get started and to make some final adjustments to the equipment. While I waited, I saw a lot of these periwinkle snails in the spartina.

periwinkle snail

It was a full moon Monday, we had seen a gorgeous moon rising the night before from the hotel pool, driving exaggerated tides. We left around high tide. Going out, the water was high making the paddling easy. We were also on an ebb flow so at times I could just relax and let the current take move me along.

Although we live on a brackish marsh, being this close to the ocean brings in a different set of marsh birds. Even before getting on the water, a small group of glossy ibises passed overhead. A neighboring house had martin houses up and we were pleased to see they had martins and not starlings in them. 

As we passed from the first creek out into Gargathy Bay (why the subtle change in name? I have no idea) we heard clapper rails calling back and forth and saw a few common terns on a bit of exposed mud. There were also plenty of willets and American oystercatchers crossing over the waters. The paddling was easy and gave lots of time to chat with the other paddlers and learn a little local history from our guide, Bill.

A turn north up a final creek led us to the in-land side of Metompkin Island, near the north end. Most of the island is protected for breeding birds during early summer but there are a few areas for landing boats and a crossing from marsh to ocean side. We landed one at a time giving me a chance to slowly float along the steep mud bank of the marsh. I could hear a bird calling but the mud was up to about eye level limiting my view into the grass. I pulled out the Merlin app and it identified the calls as a willet, but not the normal call. Just then, the willet lifted up out of the grass. Another win for Merlin! 

Our boats waiting for our return trip

Just down the beach from our landing spot half a dozen black skimmers rested on the beach. Bill had talked about their feeding behavior, skimming along the creek surface waiting for some food to hit their bill which they rapidly close, easier. It was great to be able to show everyone these amazing, and strikingly colored birds. A few of us were able to see them skimming later as we unloaded boats.

Beach at Metompkin Island

The day was hot and a dip in the ocean called to us. Dipping our toes into the water, we were surprised by how cold it was. I was expecting cool bath water temperatures, not, jump-back cold. We slowly made out way out into the crashing waves. We could see some others in our group were much further out but not any deeper. The beach had a surprisingly shallow slope. We never really made it into water much above waist level. 

My wife and I returned to the beach and took a walk before lunch. As mentioned, the island is mainly a breeding ground for shore birds. Least terns flew back and forth occasionally diving into the ocean for a small fish. Lazing on the shore just above the tide line were a range of laughing and herring gulls.

Least Tern taking a break on the beach

 Sharon spotted a piping plover in amongst the shells and rocks midway up the beach. After a minute, it scurried down close to the water and joined a second one. Piping plovers, along with the least terns, really depend on these protected beaches along the barrier islands and don't often get far inland, even along the Chesapeake Bay near us. Getting to see both species is a real treat that we don't get every year.

Piping plover

How cute is that?

On a more human note, from Metompkin, you can see up to Wallops Island and the launch complex. One of the women fishing when we first put in mentioned that she comes out to the boat launch to watch rockets. We are able to see launches, especially evening and night ones, from our house but it takes several seconds before their visible. Here, you could see, and hear, it right from take-off.

By the time we headed back in, the water level had really fallen. The creek we came in on was now a mere trickle. Bill had hoped to take us further north on the creek and come back via another route but that wasn't to be. We loaded up the boats and had to walk them about 100 yards to deeper water. Luckily there was enough water that the boats could float with us guiding them along from the exposed mud.  Once we found a big enough channel to get in the boats we still had to hug the edge of the grass to stay in a channel deep enough to paddle. Even when things opened up, we had to keep finding the channel as the water outside the channel was often only a foot or two deep. In those cases, paddling stirred up the mud as much as propelled you forward. A few people ran aground but with enough effort could work themselves loose without needing a rescue pull. 

Gargathy Bay was now a large mud flat with a creek running around the outside edge instead of open water. You can see the different route we took coming and going in the map above. The channel was wide enough that it was easy to paddle giving time to watch all of the birds that had flocked to the mud for feeding.

Once the boats were loaded on the trailer and the cars packed, we were ready for a cool snack. Bill had mentioned the local town was having an ice cream social. Unfortunately, that didn't start for another two-and-a-half hours. Too long to wait around, especially since we still had a two hour drive home. 

We had a great time paddling an area we probably wouldn't have found on our own, saw a few bird species likely for the only time this year, and had a great day.  We look forward to paddling these waters again.

A Pile of Intrigue

This past fall we had several northern flickers migrate to or through our backyard. While flickers are year-round residents here, we usually see an influx in the fall. Seeing multiple flickers land in the yard and start probing for insects is one of the joys of fall.

eBird map of yellow-shafted northern flicker for June and July (http://ebird.com/map)

eBird map of yellow-shafted northern flicker for October through December (http://ebird.com/map)

We also have a lot of hawks moving through in the fall and occasionally they will take a bird in the yard. One day we found this pile of feathers in the lawn, a sure sign someone, probably a Cooper's hawk, had taken a flicker and started removing the feathers. While sad that there is one less flicker around, this is the circle of life and it allows another bird to continue living.

 

It is quite interesting to see what must be the belly feathers with the dark spots on the ends and how loose and fluffy they are compared to the more commonly found flight feathers.

And speaking of flight feathers. There were several of those here too. What we found really interesting was that not all of them had the yellow-shaft that the local yellow-shafted race (https://www.allaboutbirds.org/guide/Northern_Flicker/id). There is a red-shafted race common in the western US but those have all red. In the field guides they will show intergrades where the two races mate but those tend to be orangeish in color. So what causes the mix and red and yellow?

A mix of red-shafted and yellow-shafted feathers from the same bird 

Some internet searching led us to an article by David Sibley in Bird Watching magazine where he talks about the various color forms of northern flickers. This mix of colors apparently stems from the birds eating non-native Asian honeysuckle berries while growing in the feathers that are red. The birds can process most carotenoids to make yellow (for the yellow-shafted) but they are unable to properly process something in the honeysuckle so it always produces red. 

Quite an interesting tidbit about these fascinating birds and another example of how non-native species can bring new chemicals and conditions into an ecosystem that the local populations aren't able to properly handle. At least this time, it seems to have a pretty neutral impact.

Note: it is illegal in the US to collect wild bird feathers. The above feathers were only brought together for the photographs.

Christmas Bird Count

 Again this year my wife and I led a sector count for our local Christmas Bird Count organized by the National Audubon Society. We have been doing the count for about a decade now and most of that time in the same sector. The stops are familiar but every year we adjust the order based on the weather to try and maximize the species and individuals encountered. Some years it is really warm and we visit the wooded areas first to get the song birds as they wake up. Other years we head to the Bay front to get early morning movements out to the feeding areas and return to the woodlands later once the birds have had a chance to warm up. And a couple of times we have been really limited by heavy fog keeping our viewing range down and the birds grounded.

This year the weather was about average; warm enough to be comfortable walking but cool enough that returning to the car or coffee shop were quite welcomed. We also had a newish birder join us for her first Christmas count. She is a fellow Master Naturalist so we knew each other.

The day felt kind of hit or miss with a few stops being very productive and several feeling slow. But that might be the way it normally is and we only remember the highlights and not the slow stops. All told we ended up recording 59 species and 3861 individuals. There isn't a lot of variation in habitat in the sector so that's a good number. In the past several years we have been in the mid-50s for species count.

Some of the highlights include a couple of boat-tailed grackles flying overhead at our second stop. We usually have to wait and hope for them in the grocery store parking lot when we break for lunch. Good to see them early and in "real" habitat. That stop also had an osprey soaring overhead. They are infrequent in winter but our sector is probably the most likely spot for a December spotting around here. 

There is one spot on the beach overlooking the Chesapeake Bay that the gulls like to hang out at. There are several break walls along the beach and just one of those coves hold about 95% of the gulls on the beach. Not sure why the like that one and not the others, but it's been consistent for as long as we have been coming here in winter. This is where we see lesser black-backed gulls on some counts. We found  at least 5 in with 750 ring-billed gulls and a few of other gull species. Wouldn't be surprised if there were a few more but everyone was moving around. 

Lesser Black-backed Gull with a lot of Ring-billed Gulls

In the past, the lessers have shown bright yellow legs that make it easy to identify (the slightly lighter dark back is sometimes hard to be confident with in the glary light). But several of these looked pink to dirty yellow. Some investigation in Sibley's after returning home confirmed they are still lessers and juveniles. Good to learn something new.

At the same stop we saw around 800 red-breasted mergansers fly by in a couple of very large groups. There were also a large group of double crested cormorants sitting and feeding on the water. We sometimes se large numbers moving out the James River to the Bay but this is a first that I remember seeing them all sitting on the water so close to shore.  This was definitely one of the good stops this year.

The next stop included some open fields where we found some very pretty eastern meadowlarks showing off with great views of them facing us. I hadn't carried along my camera and by the time I got it, they were moving parallel to us so not a photogenic. But any bit of bright yellow in winter is a good find.

Eastern Meadowlarks

We also saw nine great blue herons all standing in a row on an island in the small marshy bay (called Mill Creek for some reason as it doesn't seem to flow in from anywhere and I can't imagine there being enough flow to run any sort of mill).

We didn't see much at the far end of the sea wall looking over the bay but did pick up a few surf scoters and horned grebes that we didn't see anywhere else.

After lunch we stopped by a small park on Mill Creek that generally has a lot of pelicans, gulls, and cormorants sitting on an old pier and buffleheads swimming in the water. Although the walk to the pier is about 40 ft, it took us 15 minutes to get there from the car. We were mesmerized by an American kestrel putting on a show for us right overhead.

It was hovering/hunting for a while right in front of us and then decided to perch on this telephone pole for a couple of minutes. After a rest, it took off and was hovering along side us. It dropped down a couple of times but never dove to the ground and caught anything. Eventually it flew off and we continued on to the old pier to see the expected birds. But quite the show for us.

Finally, we had prioritized a marina we always visit towards the end of the day. It is often getting dark or we are exhausted by the time we get here. It offers not a lot of new and unusual species but it has better and more varied habitat than the more urban park and built-up beach that we usually do first and only provides rock pigeons, gulls, and starlings. And it was a good move as we saw 19 species there. This included a pair of belted kingfishers hunting from the boat masts and a row of 11 killdeer all sitting on a private dock across the creek. Just sitting there. Another unexpected sight for the day. 

We did stop and count the 75 pigeons and 200 ring-billed gulls at the beach. Surprisingly, no starlings. But don't worry, we saw plenty earlier in the day. But it felt much better doing that after the nice experience at the marina. 

Once again we had a fun and productive day on the count and provided more useful data on the changing bird populations and distributions. For example, the lesser black-back gulls were quite the amazing find the first year we found them. Now, only a handful of years later, they are almost expected. 

. 

The fox

 Saturday morning I went out in the yard looking to see if any spring migrants had come in overnight. Walking out past the shed I could hear the baby chickadees calling from their nest box and the parents flying back and forth through the nearby pear tree. Otherwise, it had been pretty quiet and I quickly got to our pier. As I approached the ramp up to it, I noticed an animal sitting about 40 ft out from the ramp.

It seems largely unaware of me at first as it was looking out over the marsh and scratching an itch. Before I got my phone out to take a video, it had turned around and was looking the other way. But still ignoring me. After several seconds it stood up and noticed me but seemed comfortable enough to take care of another itch. During that time I tried moving away from the base of the ramp. I wouldn't have as good of a view, so not video, but I was afraid I was blocking it's path off. It is about six feet down from the pier to the ground. 

It watched me as I stood to the side and then moved to get a better view again. So I turned to walk away, better to give it the space it wanted than to stress it or make it aggressive. About five steps into my retreat, I heard it jump down into the reeds.

We see the foxes around occasionally and even catch them on our camera trap.

But this is probably the closest, and longest view that I've had of the fox. A lovely experience.

A Dismal Spring Day

Yesterday, my wife and I enjoyed the unseasonably warm weather here in SE Virginia by looking for spring migrants at Great Dismal Swamp National Wildlife Refuge. Dismal Swamp is a great place to catch some early migrants, especially warblers. While I'm sure there are plenty of migrants later in spring, once the dense trees fully leave out, there's no hope of seeing anything much. We try to time our annual visit to when the early wave of warblers are coming through and the leaves aren't too dense. 

We often times start at Jericho ditch with the mistaken belief that this is the year we will actually see a Swainson's warbler. The Swamp is one of the best locations in Virginia to find this skulking warbler that allaboutbirds.com says "tends to remain frustratingly hidden in the understory." While others have heard it at Jericho Ditch on a few guided walks we have taken, we've never comfortably identified the song nor come close to seeing one. This year my wife suggested forgoing that annual disappointment and go to Washington Ditch boardwalk which we usually prefer for the rest of the birds. 

Even in mid-April the trees were well leafed out so we started with a lot of songs and no sightings. After some searching we ended up finding a group of yellow-rump warblers, actually late leaving this area, not early arrivals. Since they are winter birds here, their song is always a bit confusing. Further down the road we heard a northern bobwhite calling. A great find as populations have plummeted around here and most of the country. I'll go out on a limb and say it will likely be the only one we hear this year. It's a personal favorite of ours so an exciting bird to find. 

This blue grosbeak was actively feeding low and close to the road giving the opportunity for some good photos. 

As we started the boardwalk we heard a pair of wood thrushes singing back and forth. One was close to the boardwalk and eventually, easy to see.  Shortly after we started down the boardwalk, my wife remembered something she left at the car and returned to retrieve it. I stayed and tried to find some of the birds singing. I was using the Merlin app to help identify the sounds. It works really well, especially to put a name to a familiar song. But here was one that I wasn't quite sure about. Maybe a Swainson's? But probably not. We never really find them. But no, Merlin confirmed; it too heard a Swainson's warbler. We continued down the boardwalk listening to the song get louder and louder. Finally, it had to be right there close. And pop, the bird hopped up to a branch about 10 feet off the ground and 20 feet away. And it sat there and put on quite a show. We were able to get excellent looks as it sat there and sang. It moved a few times just a tree or two for about ten minutes. Finally, it hopped down onto the ground and disappeared behind some trees and fallen limbs. Singing the whole time. 

The real glory at Washington Ditch is the number of prothonotary warblers that nest there. I even have a picture of one nesting in a hollow about a foot off the railing at waist height. While none were that close this time, they were out in force. We never went more than a minute or two without sweet-sweet-sweet-sweet ringing out. 

As the morning wore on birds were fewer and further between. But there are also a lot of great native plants in the swamp. As my wife pointed out, good to see a bunch of aggressive plants that aren't invasive. 

The greenbrier (Smilax) and coral honeysuckle (Lonicera sempervirens) were blooming.

There were also several large, flying insects. Zebra and tiger swallowtails are common. We also saw a viceroy (might be the first one I've recognized in the wild).

There was also this beautiful ebony jewelwing damselfly.

Overall, a great day with some exciting and unexpected birds and lots of engaging nature.