Q: We have the usual compliment of nuthatch, black-capped chickadees, cardinals, mourning doves, etc., and a magnificent red-bellied woodpecker, who is ravenous. I think it is a mature male, but I’m not sure. It had been here through late January until a week and a half ago when it stopped coming.

I was sure it had died, when lo and behold, it appeared again today. Can you think of a reason it disappeared for about two weeks -- is this nesting season? Is there any way to determine which is a male and which is a female?

-- Carole, Lenox

A: There could be any one of a dozen reasons, including a fright, a new found food source too good to pass up, a female worth wooing, it has been there all along and you just missed it, it found your feeders after its early winter food sources dried up, and found another to augment yours. Perhaps subtle changes in weather.

Last Saturday, we noticed English sparrows foresaking our feeders for an afternoon of frolicking and housekeeping. Yes, on that lovely afternoon, a pair of English sparrows were "bonding" in a suspicious sort of way, between breaking grasses with which they began constructing a nest in one of our two bluebird boxes.

In the other box, not far away, a male bluebird spent the afternoon, flying in and out of the box or sitting on top. It may be too early to say this begins the season of change, but it looks like I am not the only one to think so.

This medium-size woodpecker, about the size of the hairy woodpecker, is primarily a forest species, but makes quite an impression when it comes to yards, accepting a handout at feeders stocked with peanuts, sunflower seeds, suet or peanut butter.

Difference between sexes (dimorphism) are subtle to some observers. The male’s red-head coloring essentially begins at the bill and sweeps up and over the head, above the eyes to the back of the head, or nape. The female, on the other hand, has a small red patch just above the bill and has only a red nape. The female’s face, breast and under parts are all whiter than the males. The male’s face and breast may be washed in a pale reddish color, and the actual red belly patch may be obscured by surrounding feathers.

Q: What is the most numerous bird to visit feeders? This is my second year enjoying this hobby and the junco bird is by far the most numerous.

-- Phil, North Adams

A: The same has been true here at our home for most of the winter this season. While the black-capped chickadee makes the most number of trips, and I have no real idea how many there are coming, the largest number at, and below, our feeders at any one time is the dark-eyed junco. Occasionally (this winter), we have had flocks of American goldfinches out numbering juncos, and last winter, it was pine siskins. But year to year, juncos seem to be the most numerous.

According to information on The Cornell Laboratory of Ornithology website (www.allaboutbirds.org) the "dark-eyed junco is one of the most common birds in North America and can be found across the continent. A recent estimate set the junco’s total population at approximately 630 million individuals." It goes on to report," dark-eyed juncos are numerous and wide-spread," though the North American Breeding Bird Survey estimates that populations have been declining by about 1.2 percent per year between 1966 and 2010, resulting in a cumulative loss of 41 percent. Partners in Flight estimates the global breeding population is 200 million.

While we are discussing bird feeders, why not check out a live bird feeder camera at http://cams.all aboutbirds.org/channel/38/FeederWatch_Cam/

Questions and comments for Thom Smith: Email Naturewatch@live.com