cobyw's Journal

Date - 3/07/24
Start time - 1:15pm
End time - 2:30pm
Location - Centennial Woods
Weather - Partly cloudy and a bit gusty, around 40 degrees fahrenheit
Habitat(s) - Deciduous, riparian, and edge habitat (Western section of park)

I documented a fairly low level of biodiversity on this outing, however I was able to observe several individuals from most of the species I did encounter. Theses circumstances allowed me to observe how birds of several species interact with members of their own species. The species I was able to observe interacting the most was the Black-capped Chickadee. Something I found interesting was how they use a mix of songs and calls when communicating, which can be hear at the end of the included audio file. Since the chickadees mostly traveled in groups of 3-5 and it is not quite their mating season yet, I assume that these communications are not part of their mating process, and instead important in building other social connections as well as alerting potential threats.
Several of the bird species I observed displayed drastically different plumages. Pine Siskins, for example, boast brown and grey earth tones to provide camouflage. The American Crow, on the other hand, has black plumage, which stands out much more. Crows are much larger than Pine Siskins, and therefore may not experience the same predatory pressure. One of the individual birds I observed, a chickadee, was flying around small trees near the edge of the park. I believe this activity was foraging, as the chickadee appeared to be investigating each tree closely. Since it is quite warm, I don't believe these chickadees are anywhere near the point of hypothermia, and therefore do not require as much energy to support their metabolisms in case of extreme cold events. All of the chickadees I observed appeared very active, and none seemed to be in a state of recovery from hypothermia or torpor. Unfortunately, my "pishing" attempts had no effect on the birds around me. "Pishing" is thought to reflect social calls of chickadees, and has an invitational effect on many other passerines. Another theory states that this sound is seen as a multi-species invitational call for passerines to flock together (Wikipedia).

Date - 3/16/2024
Start time - 11:00am
End time - 12:30pm
Location - Jones Pond, Moristown, NJ
Weather - 60 degrees fahrenheit with minimal wind and clouds
Habitat(s) - Wetland, small pond, riparian, woodland

Many of the species I observed exist in this habitat year round. if a stable food source exists, a bird may forego annual migration. For example, the Belted Kingfisher requires proximity to open water to indulge its diet of small fish and stream macro invertebrates. Luckily for the Kingfisher, Jones Pond rarely freezes over in the New Jersey winter, so the bird faces no pressure to migrate. Another perennial New Jersey resident is the Downy Woodpecker. Similarly to the Kingfishers, these birds have no issue sustaining their diet through the winter. Additionally, these woodpeckers can combat cold conditions by taking shelter in trees they have bored holes in.

A facultative migrant species that may be arriving in Burlington around this time is the Canada Goose. These birds tend to winter around the Southern US and summer in Northern Canada. They are mostly grazing birds, meaning they require fields with vegetation to obtain nutrients. The climate in Burlington doesn't usually allow vegetation growth and the onset of Spring until April, so it still may be a bit early for Geese here. The main disadvantage of migrant birds arriving to Burlington in April is the unpredictable conditions depending on the year. It isn't winter anymore but also isn't Spring quite yet, and these conditions can have major effects on returning birds.

Surprisingly, all of the species I observed are year-round residents on New Jersey. This is surprising to me because March usually indicates a changing of seasons in New Jersey. Open water and emerging vegetation can also be found around this time. If I did see migrant species, they would likely be Canada Geese or Red-winged Blackbirds, which are both commonly around bodies of water.