Archivos de Diario para marzo 2020

06 de marzo 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 ( 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.

Anotado en marzo 06, viernes 23:29 por mreilly20 mreilly20 | 5 observaciones | 0 comentarios | Deja un comentario

26 de marzo 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.

Anotado en marzo 26, jueves 04:06 por mreilly20 mreilly20 | 5 observaciones | 0 comentarios | Deja un comentario