Spring brings new growth on our trees, many new flowers brightening the fields and forests, birds returning from wintering areas, and the time most mammals are giving birth.

It’s also a time to remind you that over the next few weeks the whitetail deer fawns will be born. Importantly, your urge to help what you assume is an abandoned fawn, must be overcome.

Born with a mottled, spotted coat, the fawn’s coloration and lack of scent have for millennia allowed it to find a spot to lay down, remain motionless and only move when “mom” comes to nurse it.

Please don’t try to help the fawn it is following its innate behavior of lying still for a week or so until the doe feels her fawn/s can travel with her and avoid predators. After a gestation period of about 200 days, most fawns will be born in the next few weeks. Let them alone.

That leads me to talk about why this time of year is the birthing time.

There are exceptions of course. Black bear females gave birth to their cubs in January. Born hairless, blind and helpless, they snuggle next to mom, who nurses them and warms them for about two months in the den. Bears were bred in late June or July, but their gestation time is rather short. Bears, otters and mink have delayed implantation, where the embryo doesn’t implant in the uterus until, sometimes, months later.

Gestation times vary among mammals. One mammal with an extremely short gestation is the opossum. From time of breeding until birth is 12½ days. The tiny young opossums (about ½-inch in size), after emerging, need to use their clawed front feet to crawl a few inches to the mother’s pouch. (Opossums are marsupials, like a kangaroo, and the only marsupial in North America.) They nurse and remain in her pouch for about nine weeks, growing amazingly quick. Later they may hop on mom’s back and hang on as she finds food.

Two mostly aquatic mammals have quite different gestation times.

Adult otters are terrific swimmers, able to outswim the fish they eat. They have a gestation time of about 60 days. The young are born blind, unfurred and helpless. In fact, even after being weaned and leaving the den, the young otters don’t know how to swim. The adults basically drag them into the water and teach them.

Beavers are a bit different. It takes 85 days for the young to be born, and they are alert, fully furred and if necessary, can swim when “hitting the water.”

Keep in mind that beavers and otters are not related. Beavers are rodents, in fact, North America’s largest rodents. The otter belongs to the mustelid family (weasels, mink, etc.)

Another common mammal with a short gestation period, of only 28 days, is the cottontail rabbit. They are born blind, without fur and helpless. They too mature rapidly, and within 16 to 18 days leave the nest depression and begin fending for themselves. Most females have four litters each summer, with five young the average per litter. Luckily for backyard gardeners, rabbits are a staple for many predators and the populations are kept in check.

Now is the time otters, beavers, deer, raccoons, opossums, skunks, mink or weasels are all giving birth and rearing their young. Not only is this a good time to “bird,” but also to OBSERVE many mammal youngsters. So get out there.

Test Your Outdoor knowledge: What North American mammal has the most teeth? A. mink; B. otter; C. big brown bat; D. opossum; E. beaver.

Last Week’s Trivia Answer: Most warbler species, even those breeding just east of the Canadian Rockies, avoid the central flyway. The grasslands of our Midwest don’t have enough forested areas for them to feed and rest on their long treks southward. Pennsylvania is in that prime migration area.

Email Barry Reed at breed71@gmail.com