Nature is doing fine all around us...adapting to the changes we make to our environment.
Sometime in the 1990s I noticed some birds chirping and swarming around one of the bridges on our bottom road.
They looked like a swallow but were definitely NOT barn or tree swallows. After studying them for a few moments and then looking under the bridge it hit me - they were Cliff Swallows.
What in the world are they doing around here - there are no cliffs in this area and then it came to me...almost all of the bridges we have now are made of concrete and replaced the wooden beam bridges the county roads and the railroads always had.

So apparently these swallows have adapted to our modern bridges to use them as an excellent place to raise a colony.
For many years I noticed they were struggling with those darn English Sparrows. The enclosed mud nests are the perfect place and size hole for those invasive and aggressive sparrows to take over the nests.

So for many years the swallows moved from one concrete bridge to another. There are 3 in our bottom...
Then a few years later I noticed the swallows had moved to the East Street bridge by Willow Creek.
I was glad they continued to colonize in this area, but sad they weren't on our bottom road.

Then after only a year or two along Willow Creek they moved back to the bridges in our bottom, which I'm happy about because they are great at catching and feeding on flying insects.

I hadn't inspected their nests for about 5 years and was amazed when I saw how they have really taken over the outside concrete beam.
During prior years they made nests in a more hap-hazard way on the beams underneath and not all in a row.

I think they figured out there is safety in numbers by mostly nesting together as shown below.
Those darn English Sparrows, which are NOT native, but brought over by some of the Pioneers a long time ago, are not as much of a threat when the swallows colonize this way.
I also have an aggressive trapping process to catch and reduce the English Sparrow population on our farm.

I've been doing this to help the Bluebird and Tree Swallow trail I've been maintaining for around 40 years.

As I'm writing this article, I continue to reflect on the number of bird and other animal species we have now that did not exist here when I was a kid...including those darn deer that have really adapted to the changes we've made to Iowa's environment and have become very fruitful and multiply.

Bird species we have now but didn't see when I was a kid: Turkey Vultures, Kestrels, Cliff Swallows, Bald Eagles, Asian Doves, and several more I can't think of right now...

The colony has been growing over the years.

I would guess the reason why some nests have fallen off or broke apart is from the vibrations created by the heavy truck traffic...but for the most part the nests appear to be "hanging in there..."

Cliff Swallows swarming around me

I was concerned in May when the approaches to each bridge were repaired. The construction crew was using a large hydraulic hammer drill, concrete saws, and all kinds of noisy equipment...Would the swallows abandon the bridge was on my mind each day they worked - well these birds are very tolerant and accepting of we noisy humans and stayed with the bridge and defended their colony.

I don't think the swallows felt threatened by my presence, because they didn't attack me like some birds do when they perceive their nests are threatened, but they definitely were annoyed with me.

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