04/04/2021 FJ5: Pomeroy Park, Old North End + feeder birds

Date:4/4/2021
Time: 10:30a-12p
Place: The old North end Pomeroy Park + surrounding neighborhoods + inside from a bird feeder just after my walk (included because they excited me)
Scattered clouds 40F no/minimal wind

All the birds I saw on my walk were year round residents. The American Robin and Cedar Waxwing (unsure if ID correct) may go south for the winter, but commonly they stay put. The European Starling, according to All About Birds, the juveniles may go slightly south by a state or two but not very far. The House Sparrows, Black-capped Chickadees and Tufted Titmouse are year round residents. These smaller birds can more easily navigate the woody underbrush and have access to more cover simply because they are smaller. Even without leaves and tree cover these birds can hide or escape into the undergrowth and become inaccessible to predatory animals. They all seem to group loosely together too, this may further help them evade predators. If one calls a warning call they are alerting not only their own species but other bird species to a potential threat. To survive the winter, as discussed previously, they have downy feathers and are able to insulate themselves better against the cold. This coupled with the counter current exchange in their feet, paired with a small overall body mass, they can stay well insulated during the ice cold VT winters. Further, they may conserve energy by staying in one place most of the day, unless looking for food. Not migrating would be beneficial because they avoid large energy expenses and are all in the same place already when the breeding season comes around. By staying put they may also have first access to the best territories and feeding grounds.

Interestingly, the Robins may go as far as Florida if they do choose to migrate. Similar to the Starlings, I would imagine these are the younger birds. Going south may be easier because it is warmer but also because there may be more food due to the warmer weather, thus allowing the younger birds the best chance of survival into the mating season. Further, the warmer the weather the more likely the trees will still have leaves providing cover from predators. This may be especially pertinent for the younger birds because they are still learning how to be a bird and survival does depend on remaining unseen by raptors or even terrestrial predators. The older birds, know the environment a little better, may have secured territories they can defend and a reliable food source therefore they choose to stay and not spend the energy to migrate so far. Coming back to VT in early April may be due to them simply not migrating that far anyway or a preferred habitat for mating. The Robin may go as far as Canada to mate, so it would make sense a few don’t go quite as far north but find similar habitat here in VT. Vermont may have a different spring/summer food source and better nesting materials for the Robins or simply better forests with better habitat as the months warm up compared to Florida habitat. Coming back early in the season ensures prime real estate and plenty of time to molt or restore their spent energy after migration and before finding a mate. The Blue Jay, I am not surprised they don’t really migrate. They have been described as ‘bullies’ and I would expect them to easily out-compete some of the smaller songbirds for food (at least at bird feeders), making it all the more easy for them to hang out throughout the winter instead of migrating. Their larger body sizes and more aggressive personalities may also deter predatory birds from attempting to hunt them.

I didn’t come across any obligatory migrants (disappointing) this time. However, for my last field journal I did come across a flock of Red-winged Blackbirds, who commonly migrate back to VT for the spring and summer months. Again, coming back early in the season would give these birds the best chance of finding ideal territories and a chance to recuperate from their migration. Additionally, it may also give them an advantage to finding a mate. As they trickle back they can pair up as soon as possible, and if you’re late to the party you simply have less mating options. I would imagine this would be especially important for juvenile birds entering their first mating season, the earlier they get back the more time they have to find a mate and possibly learn from other birds how to court a mate. Some disadvantages to getting back to Vermont as early as April is that it is still pretty cold. As we witnessed not too long ago, it may still snow. This could pose a challenge to southern birds migrating north because they won’t be used to the cold climate and the abrupt change from mild temperatures to temps below freezing could threaten their survival.

Julkaistu huhtikuu 5, 2021 04:43 IP. käyttäjältä jamiek347