09 de abril de 2020

April 7, 2020

Tuesday, April 7, 2020
Wallingford, PA
(Habitat: backyard bird feeder; suburban deciduous forest edge/field)

9:30 – 11:00 am: It was a warm spring morning, about 65 degrees F and partly cloudy. When I first headed out, the skies were blue and the sun was bright, but as time went on, the sun went in and out and was hidden behind clouds by around 10:30 am. Since most of the parks are closed near me, I ended up going back to the field that I did my last journal at—at the edge of a small patch of deciduous woods. I also started out at our backyard bird feeders because just the day before, our newest visitors included some American Goldfinches and a Red-winged Blackbird! But this morning, the only visitors were a Song Sparrow and an Eastern Gray Squirrel.

Once I arrived at the field, I encountered lots of robins and a few chickadees! According to the Audubon Society, American Robins tend to be permanent residents in Pennsylvania, and if they are migrating, they may have only come from a few miles away. Their winter food source is primarily fruit, so they are probably able to survive in our area off of winter shrubs that produce berries, especially now that our winters are getting warmer. However, climate change must impact their migration patterns if they do migrate, making them more susceptible to extreme spring weather if they migrate early. Black-capped Chickadees are definitely permanent residents of this area; I imagine that as a flock species, they use the power of numbers to stay protected from predators and find food during the winter. They are also able to eat a fairly diverse diet of fruit, insects, seeds and animal fats, making them adaptable and resilient to changing conditions.

About 10 minutes after I got to the field, I noticed some movement in one of the arborvitae trees that line the fence separating the field and the woods. I saw a tiny olive-gray bird, but it was deep in the branches so I couldn’t make out many other features. I thought it might be some kind of sparrow because of the black and white lines on its wings, but it flew out of sight before I could get closer. I turned my focus to some of the other birds around me—including a fair number of House Finches, House Sparrows and a few Song Sparrows—but it wasn’t long before I noticed the same bird in a tree a few feet away. I was able to creep closer and as it hopped in and out of sight, I thought I saw a flash of red on its head. Then it hit me! “Oh my god did I just see a Ruby-crowned Kinglet?” I actually asked myself out loud, a bit too excited by the fact that what we learned in class was being applied in the real world (as a budding bird nerd does). But it was so brief that I couldn’t be sure. Suffice it to say, this little guy continued to cross paths with me throughout the next hour and a half, always in one of the arborvitaes and keeping himself well-concealed but confirming my original ID. They may not be the rarest bird, but I had never seen one before learning them for our quiz, so I was delighted by this one, and how many chances he gave me to identify him! According to Audubon’s and Cornell’s websites, Ruby-crowned Kinglets are short-distance migrants who winter in the southern US and Mexico. Pennsylvania is considered non-breeding grounds for them, so this one was likely on his way to breeding grounds further north in New England and Canada. Since facultative migrants tend to respond to short-term stimuli such as changes in vegetation and temperature, warmer weather and the return of foliage likely brought this Kinglet up here.

Mini Activity: I didn’t see any obligate migrants on this excursion, but I looked up the distances for the Ruby-crowned Kinglet and two other possible short-distance migrants, Song Sparrows and American Robins. The Ruby-crowned Kinglet may have traveled the furthest—they have been seen as far south as Guatemala, but many winter in Mexico, so I used the distance from Mexico City to my hometown, Wallingford, PA which is about 2500 miles. Then, both Song Sparrows and American Robins are known to winter down in Florida, so I measured the distance from Tampa—about 1025 miles. All together, these three birds’ possible journeys total 4550 miles! And they all still have a ways to go if they’re still en route to their northernmost breeding grounds.

Publicado em 09 de abril de 2020, 03:51 AM por mreilly20 mreilly20 | 7 observações | 0 comentários | Deixar um comentário

26 de março de 2020

Wallingford, PA - March 24, 2020

Tuesday, March 24, 2020
Wallingford, PA
(Habitat: suburban deciduous forest edge/field)

5:35 pm – 7:00 pm: It was golden hour, with beautiful, clear skies, about 55 degrees F and no wind. Since I’m home now, I went to a field that belongs to a synagogue behind my house—it’s situated at the edge of a small patch of deciduous woods. I live in a suburb of Philadelphia, and this small patch of woods is probably the biggest patch of continuous woods in my immediate neighborhood and hosts a surprising variety of wildlife. The birds were very busy as it approached dusk, flying in from the where the main roads and houses are to roost in the trees at the edge of the woods. From my start time to about 6:30 pm, the birds I saw and heard were primarily American Robins and Blue Jays. There were more robins than I could count, but I suspect I encountered at least 50 during my excursion. Most of them were roosting in the trees, and a group of about 10-15 were foraging in the field.

Observations/Interactions: Soon after I arrived, 4 Blue Jays congregated on a few adjacent branches in a tree at the edge of the woods. I noticed that the jay on the highest branch was the only one with its crest held erect; the other 3, sitting on lower branches, had their crests held mostly flat. They were all making their “jeer” calls. They remained for about 2-3 minutes before they all flew away. They all arrived at around the same time so I couldn’t tell if this was a territorial interaction (if the higher jay had its crest up in defense) or if they were part of a family group and responding to another threat together.

At around 6:30 pm, the neighborhood sparrows and finches seemed to suddenly converge on the area, and I spotted a male and female House Finch in a nearby tree. The female was chirping and fluttering her wings, and the male followed behind her as she hopped from branch to branch. At one point they appeared to touch beaks, which I’ve read may have been the male regurgitating food as part of a courtship ritual. To make things even more interesting, I spotted them again later, but this time there was another male. The female repeated this behavior with both, and it felt a bit like I was watching an episode of The Bachelor: House Finch Edition. In all seriousness, this behavior certainly fits in with the timing of warmer weather and longer days; spring is here in Pennsylvania and mating season has begun!

Spishing: Standing in the same spot, I heard the “cheeps” of House Sparrows coming from the arborvitaes that line the private driveway that runs alongside the field. I “spished” for them and they were very curious! They ventured closer to me and there was one brave male that came out of the cover of the dense branches to investigate, but I counted about 4 other individuals following behind him. Earlier, I practiced spishing when a Gray Catbird boldly perched in a tangle of shrubs right in front of me. It looked directly at me and seemed to consider my strange noises for a few moments, cocking its head and hopping to another branch to get a better view. I didn’t want to distract the Catbird or the sparrows for too long, so once I finished, the Catbird flew away and the Sparrows retreated. As to why birds respond to spishing, my guess is that it sounds enough like the warning calls of many birds (like chickadees or titmice) and birds may want to investigate if a threat is present. Birds that form flocks may be more interested, too, as they rely on group communication to stay safe and alert.

Plumages: In thinking about the plumages of the male House Finches and male House Sparrows, and how they compare to male Northern Cardinals, I noticed that the two species that have less conspicuous plumages (the red of male House Sparrows is considerably less vibrant than a male Cardinal’s), the finches and sparrows, tend to be birds that form flocks. Though there’s safety in numbers, is it possible that a flock of birds could also act like a “buffet” for a predator, thus the more a bird blends in with its surroundings, the harder it is to pick off? When I observe Northern Cardinals outside of our bird feeders, they seem to be alone or in pairs. During the breeding season, the males are very visible (and audible) which seems riskier, but perhaps because they don’t form flocks, they’re not as obvious to predators? And/or the benefits of effectively attracting females outweighs the risks of predation.

Publicado em 26 de março de 2020, 04:06 AM por mreilly20 mreilly20 | 5 observações | 0 comentários | Deixar um comentário

06 de março de 2020

Old Mill Park - March 1, 2020

Sunday, 3/1/2020
Old Mill Park, Jericho, VT
(Habitat: Northern mixed conifer forest)

11:00 am - 12:30 pm: it was a brisk day, about 15 degrees F, mostly overcast but with blue skies peeking out every so often. The day’s most interesting bird observation actually happened while I was waiting outside my friend’s house, before we even left for Jericho! There appeared to be a Common Raven and an American Crow squabbling in the air. The crow was cawing loudly and dive-bombing the raven. The raven would dodge the crow by flipping over or making a sharp turn; they would fly apart from each other for a few seconds before the crow went for the raven again. According to some brief research, I found that crows and ravens fight often, particularly during their breeding seasons, as they are nest predators of each other. These interactions also tend to be instigated by crows—despite the size difference between the two Corvids—and multiple crows often mob a single raven (https://www.allaboutbirds.org/news/crows-have-a-mob-mentality-toward-ravens/). I wonder if this interaction was a territorial or food-related fight, since their breeding seasons haven’t quite started yet and winter food sources are likely still scarce?

Now for the main event: the park we visited was situated along the Browns River, behind the Old Red Mill in Jericho. We entered from the mill’s parking lot, where the landscape transitions from a meadow to a denser mixed forest and then to the river/waterfall. This part of the river is very rocky, so most of the trees around the entrance and by the rock outcroppings were snags—the living flora was mostly made up of shrubs and saplings. With so many hiding spots and some berries, we thought this might be a good place for seeing birds on a cold day. But after watching these snags for a while and tapping on hollow trunks without seeing anybody, we decided to head up a steep incline where the forest was denser with living trees. As we moved up, maple, ash, cherry and staghorn sumac transitioned to predominantly white pine and eastern hemlock. Unfortunately, the only birds we actually saw on this trip were three birds that flew overhead and were difficult to ID. They were gray on the undersides of their wings and bellies, and their flight pattern resembled that of European Starlings.

At the top of the slope, we could hear faint birdsong coming from the meadow down below. We still couldn’t see any birds but we think we heard some black-capped chickadees and house sparrows down the hill, where the creek ran through the meadow. The birds were likely spending this cold day in this edge habitat—in their flocks or in warm snags, close to where winter food sources like berries could be found—and not in the conifers we were standing near. I think the time of day wasn’t the best for birdwatching either; since birds are most active at dawn and dusk, they must have been budgeting their energy and body heat while we were there midday. I know there are many reasons that they’re most active at the beginning and end of each day, but during the winter, my guess is that it is even more important for them to maximize their feeding times to either prepare for a cold day or a long night. The only other birds we heard at the top of the slope were a passing American Crow and the high pitched, rapid whistle of what I think was a cedar waxwing, but I could not see the source. I heard it on the side of the slope that was closer to the water.

We found an interesting snag (three of the photos linked to this entry) near where I heard the Cedar Waxwing. It was completely hollow and short—about shoulder-height. It looked like the trunk had split at some point, but the rest of the fallen tree was either completely covered by snow or had since been removed. There were a lot of cavities that appeared to be the work of various woodpeckers on its relatively small surface area. The biggest hole was oblong and looked like that of a Pileated Woodpecker. This snag didn’t seem to be a very warm or safe hiding place at this point because the top was completely exposed, so I wonder if those holes had been formed either before the tree fell/died or sooner after. I was also curious as to why so many of the holes were close to the ground, even if they were just for feeding. A bird would likely still be vulnerable as it fed at the base of the tree. Nevertheless, the safer snags near the entrance/meadow are important shelters for birds that give them easy access to/fast escape routes from winter food sources in more open habitats.

Publicado em 06 de março de 2020, 11:29 PM por mreilly20 mreilly20 | 5 observações | 0 comentários | Deixar um comentário

19 de fevereiro de 2020

Centennial Woods - February 16, 2020

Sunday, 2/16/2020
Centennial Woods, Burlington, VT
(Habitat: Northern hardwood forest)

11:00 am: It was a gray Sunday morning, fairly chilly at about 20 degrees F with a brisk wind. Before we even entered Centennial Woods, my friend and I had the treat of seeing a large hawk fly above the trees at the edge of the woods along Catamount Drive. As it flew from tree to tree, we were lucky enough to see it take off from behind, so its red tail was visible and we identified it as a Red-tailed Hawk! Its large wings seemed to make it difficult to take off at first, but after a few flaps it glided smoothly into the next tree.

As we entered the woods, we encountered a female Northern Cardinal in a tree along the trail where it runs alongside the residential development. She was briefly joined by a male before they both flew in the direction of the woods' entrance behind us. To take off, they hopped a few times on the branch, as if deciding which direction to head, and flapped their wings 2-3 times, before taking off with ease.

We moved on, deeper into the woods, until we found ourselves in the frozen meadow in the center of Centennial. It was the perfect spot to see and hear all of the activity going on in the forest’s edges. There was a mixed-species flock of Black-capped Chickadees, Tufted Titmice and Nuthatches nearby. They were all hopping between the understory and at the bases of trees. The Black-capped chickadees were the easiest to see in flight and seemed to travel the furthest, enough to flap once or twice and glide to their next destination. On our way back out of the woods, we heard the croak of a passing Common Raven and saw it gliding over the trees on East Avenue. In my notes, I wrote that it glided “like someone impersonating an airplane:” its outstretched wings tilting and turning gracefully with the wind.

Overall impressions: we observed the most activity in edges; I’ve always loved observing edges because they’re rarely quiet. We stood in the middle of the meadow listening to birds communicating to each other from the safety of the trees on either side (I uploaded a recording of a White-breasted Nuthatch "conversation"). In terms of flight patterns, the Passerines we observed (Northern Cardinal, Black-capped Chickadees, Tufted Titmice, Nuthatches) flew in short bursts, their elliptical wings able to navigate the tangled branches and brush. The Common Raven was an exception to this, its soaring flight more like that of the Red-tailed Hawk. Granted, we didn’t see the Raven take off or land, but I’m curious what wing type they have? They almost look like the slotted high-lift wings of raptors—long, their primary feathers spread in flight—and less like elliptical. Slotted high-lift wings would make it easier for them to soar and glide as they do.

Publicado em 19 de fevereiro de 2020, 02:52 AM por mreilly20 mreilly20 | 2 observações | 0 comentários | Deixar um comentário

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