Double Bridges – a Comparison

Lighthouse Road crosses the East River on two at-grade bridges about a half mile beyond the St. Marks NWR Visitor’s Center.  I once spent a mid-summer morning walking slowly back-and-forth along the road edge where it crosses the rich hydric hammock along the river.  I had wanted to get a sense for the rhythm of the day and I took journal notes of what I saw. Today, exactly five years later, I took that same walk to see how things had changed.

This is a shallow arboreal canyon. The trees on each side form the walls, but for most of its length the area above the road is clear sky. A single walking loop is about a quarter mile, the exact distance depends on how far past each bridge you go before turning around. I started walking just after 6:00 am and continued for three hours. With frequent stops to look and listen, that’s enough time for about a dozen loops.

Some differences between my walk in 2016 and my walk today were of little importance. The East River was higher this year. This morning, its slow-flowing blackwater covered much of its shallow floodplain. It was lower in 2016, but water was flowing in both channels. The first walk was on a sunny clear day. Today, there was a high fog layer that morphed into a low cloud cover after dawn. Both days were hot. 

The woods themselves have changed in predictable ways. Trees have come down creating openings in the hammock. Hurricane Michael dropped a few and others simply aged out. The central branches of an old elm by the first bridge died and collapsed this summer and a few of my favorite dead snags have fallen in the intervening five years. Cascading grape vines have gotten thicker and the understory trees have grown.

There are phenomena that show little variation over the years. Hunting bats give way to hunting dragonflies as the day lightens. The frog chorus, mostly pig frogs and green tree frogs, peaks at first light and mostly stops by sunrise. Grape and swamp dogwood are ripe in late July, but persimmon and beautyberry are still ripening. 

Some birds are predictable and easily found every year. Pileated Woodpeckers and Red-shouldered Hawks are noisy and have calls that can be heard for half a mile. Northern Cardinals, Tufted Titmice and Yellow-billed Cuckoos are not as loud and don’t call as often, but are still easily heard. Ruby-throated Hummingbirds and Red-bellied Woodpeckers aren’t shy and are always easy to spot. In 2016 I located a hummer nest near the first bridge. Given how many hummingbird sightings I had this morning, I suspect that there’s a hummer nest there again this year.

There was one stark difference. In 2016, I had several hundred waders flying over starting at 6:40 am and continuing, intermittently, until 8:30 am.  They were coming off the big rookery on East River Pool. I recorded Great Blue & Little Blue Herons, Great & Snowy Egrets, White Ibis and Wood Storks. Today I had a single Great Egret fly over.

There has been a breeding rookery and winter roost at the North end of East River Pool for as long as I can remember. This year it was deserted, possibly due to the extremely dry weather in late Spring that turned East River Pool into a series of mud flats.

I ended up doing over three miles on my walk this morning. I had fifteen species of birds that I had also found in 2016 including Yellow-throated Vireo, Prothonotary Warbler and Acadian Flycatcher. In addition to the missing waders, I didn’t find Summer Tanager, Barred Owl or Red-eyed Vireo this year, but some changes are just due to chance.

The refuge changes; daily, seasonally and over the years. Come down to St. Marks and see for yourself.