Brrrrrrrr. The New York City metropolitan region just logged in its coldest temperatures of the winter so far. It was so arctic the frigid air mass was historic and one for the record books.
The low temperature at Central Park in New York City on Valentines Day dipped to a daily record low of 1 degree below zero. The coldest Valentines Day on record in New York City in more than 100 years and the coldest winter reading at Central Park in more than 20 years since January 19, 1994, or when Bill Clinton was President. The coldest temperature ever recorded in Central Park occurred on February 19, 1934 when it was Siberian at -15 degrees.
The harsh cold wasn’t just confined to Central Park. It was ice cold at John F. Kennedy International Airport on Sunday where the temperature dropped to 1 degree, which broke the old record of 4 degrees set in 1979. LaGuardia Airport tied the record low of 1 degree, previously set in 1979. The low temperature in Newark, NJ dropped to zero early Sunday morning, which also tied a record set back in 1979.
Around Sandy Hook Bay, the polar vortex sent low temperatures to a frigid 4 degrees on Sunday morning and kept very cold temperatures all day across Lower New York Bay. Highs were only in the teens. The cold was especially cruel as it followed a few weeks of temperatures averaging above normal. Temperatures were an extraordinary 30 degrees lower this weekend, compared to highs last weekend. Old Man Winter was clearly in charge.
With arctic air in place, how did the little sparrows and other songbirds survive around the estuary from the brutal cold? It turns out these little birds are not so delicate or dim-witted as we might think.
Image above from https://www.facebook.com/NWSNewYorkNY/photos/a.188187191210604.50415.177148895647767/1220950777934235/?type=3&theater
Although many birds head south for the winter, quite a few of our feathered friends stay put around Sandy Hook Bay and New York Harbor to be in a better position to find prime nesting territory next spring. Some other birds that nest in Canada or northern New England will also arrive here during the winter so they can have a shorter migration to better nesting sites in the spring than birds who overwintered in Mexico or South America.
Yet, the trade-offs to staying around New York City for the winter can be risky. Sparrows and other songbirds have to quickly learn to adapt to changing weather conditions and food resources. With few insects to be found, a bird’s diet changes almost exclusively to berries and seeds.
Food is important for a bird’s survival. One reason why so many birds migrate south is not due to cold temperatures, but a plentiful supply of food sources, which are not available around New York City in the winter months.
For many birds, feathers serve as excellent insulation and the oil that often covers feathers provides waterproofing. No doubt the best downy winter coat around. It allows them to keep warm and dry.
On a frigid day, birds will puff out feathers to trap warm air from the bird’s body and to heat cold spaces between feathers. A puff-up bird means more trapped air in the feathers, which means a warmer bird.
But there is more to keeping warm then just fluffing feathers. Birds are warm-blooded creatures with an average temperature of around 105° Fahrenheit. In order to keep this high metabolic rate going, birds need enough fuel or food each day to keep warm. Birds are able of endure bitter cold, even extreme cold, as long as there is sufficient food to be found.
Every calorie counts in order for birds to survive winter. Birds need to find enough food to get through the day and also build up adequate fat reserves for the coming night, all with limited daylight hours.
In order to keep warm at night, many birds will participate in a group shiver to generate heat in the flock. Shivering will raise their metabolic rate. The down side, it will cause more calories and fat to be depleted. Birds need to eat every day during the winter to keep healthy and happy.
One main strategy birds have to make sure they have food handy is to hide or cache their provisions, especially seeds. Caching is the activity of collecting and hiding food to be eaten at a later time by birds. It turns out many birds, especially land birds, are good at caching food.
In Vermont, one researcher found that Black-capped chickadees could locate a cache of high-energy food 28 days after the birds had hidden it. Another researcher found that chickadees will remember which caches have the fattest, highest-energy foods and consistently raid those caches first. They're also clever about hiding their caches. Rather than create one big storehouse that would be easy to remember, they scatter their caches around their territories in case another animal raids one cache. Pretty smart for a birdbrain.
The truth is, it isn’t always necessary to worry about how birds keep warm during the winter, especially adult birds that have already survived their first winter. Birds often have plenty of ways to survive even the chilliest nights. Yet, people that know birds tend to want to help birds by providing food, shelter and other necessities to make a bird’s life a little less stressful in an urban-suburban environment. People that appreciate wildlife want to make sure our feathered friends enjoy winter outside just as much as humans enjoy winter in our warm, heated homes.