Birding at Washington Crossing Park

On March 24th, I spent the evening in Washington Crossing Park along the Delaware River in Pennsylvania. I was there from 4:40 pm to 6:48 pm. It was a beautiful day, sunny, calm, and around 50 degrees Fahrenheit. This park has a great diversity of habitat. I started off in a sparsely wooded area along the Delaware River. Then I moved toward field edge habitat, followed by marshland and lake habitat. I observed 31 species, most notably a Red-headed Woodpecker which was being reported from that location.
Another interesting bird that I got to see, and one that I love to see no matter how many times I already have, was the Brown Creeper. One of the reasons I love seeing Brown Creepers is because of how cryptic they are. I first heard the bird and had a very difficult time locating it from just that. Its very high-pitched call made me question over and over again which exact direction the sound was coming from. Then, when I finally got a glimpse of the bird, it still did a great job of hiding. Their cryptic coloration is some of the best camouflage I have seen. The various browns on their back make them blend seamlessly into a tree trunk. However, cryptic coloration is not the only plumage type that can provide good camouflage.
I also observed a few Dark-eyed Juncos feeding along the dark, paved roads going through the park. Their countershading plumage is a perfect example of energy efficient camouflage. The entire top half of these birds are a dark slate color which, on certain surfaces, provides great camouflage. However, the belly of these birds is white. This saves energy because they don’t have to make pigments for these feathers. A final plumage type that can provide defense against predators is disruptive coloration.
The Red-headed Woodpecker that I was lucky enough to see that day was a great example of disruptive coloration. This bird can be broken into just a few major blocks of color: a completely red head, a white belly, and a majorly black back with a large white patch in each wing. While this won’t directly camouflage the bird into its surroundings, it breaks up the general outline of a bird, so it may be more difficult for a potential predator to identify as food.
Another species that I was happy to observe was a large group of Yellow-rumped Warblers. While a few individuals will winter over in PA, this group was likely a migratory flock on its journey to breeding grounds. They had started their pre-alternate molt and were singing their full songs rather than their typical call note which can be used to pick them out in the winter. Since the whole migratory process is very taxing on birds, these Yellow-rumped Warblers were constantly foraging and pausing occasionally to sing. Since I was so excited to see warblers (almost) in breeding plumage, I pished for a little bit to see if I could get a closer look. I think most of the individuals were too preoccupied with their feeding to care about my pishing, but a few came down briefly to see what was going on. I imagine that this sound is so enticing for small birds because it somewhat imitates an alarm call. Since many small birds are preyed upon by tactics of surprise, identifying the location of potential predators helps their survival. So, they may come in to see why the noise is being made.

Posted on 26 de março de 2020, 02:03 AM by phil_stoll