Answers from the Robin Expert
|Questions and Answers|
From: Cleveland, Ohio
Q: Can you tell a migrant just by its size or color? Are resident winter robins smaller than the migrants that arrive in the spring?
A: Although different populations of robins are slightly different sizes and the color intensity of the plumage varies somewhat geographically, robins don't really show the cut-and-dried plumage variations that populations and subspecies of others birds do. On average, robins are smallest in the warm, humid southeastern US, and smaller than average along the humid coast of northern California and the Pacific Northwest. Robins are largest in the high, dry Rocky Mountains, northern Great Plains, and northern deserts of the West.
Robin plumage is darkest in birds in the Pacific Northwest and in Newfoundland—both places where the humidity is exceptionally high. The amount of white in the tail is largest in the East and smallest in the West. An isolated robin population in the Baja California Sur is exceptionally pale.
But robins live up to their scientific name, Turdus migratorius (the "migratig thrush"), wandering widely and unpredictably in winter and often ending up in spring in entirely different areas from where they were raised, so there's a lot of mixing. That means that size and color differences among populations are subtle at best; even with perfect views, we can never be absolutely certain where robins came from by either size or plumage.
From Grant, Minnesota
Q: Are there states where robins do NOT sing the territorial song and set up territories for nesting?
A: Actually, robins probably at least occasionally breed in every state, simply avoiding the extreme south of the Gulf States. They don't nest in peninsular Florida, but apparently can nest in the northwestern part of the panhandle. You can see by robin range map where they can be found "year-round," and they probably at least occasionally nest in the southern parts of that range.From: Muskego, Wisconsin
Q: How much does a single robin change when it's back in the spring? We have one lone robin that comes to our heated waterer twice daily. However, we noticed that its colors are much brighter than they were last week and it stays longer.
If the week was warmer than the previous week, it's possible that he was not erecting his down as much. His feathers would lie flatter and appear more intense in color. Also, it could be a different individual, especially if his behavior had changed too.
Q: Do robins in the yard do a mating dance?
A: Mating dances and other complicated mating rituals are usually found in birds that mate for life (such as eagles and cranes) or in species that don't pair up for long (such as prairie chickens and hummingbirds). In both cases, the birds invest so much energy in mate selection that they are at risk of predation during the rituals. In birds that mate for life, both need to make absolutely certain that they've chosen an ideal mate because they'll be together for a long time. In birds that are only together for mating, with only the female raising the young, the female must be very choosy about finding the best male to ensure that her young will be genetically strong and healthy.
Robin pairs usually stay together just for the season. If they don't succeed in raising their first brood, they often move on within that same nesting season, so they don't need to put the energy into this kind of courtship ritual. The songs of a male are an excellent signal to a female that he is fit and healthy, and also serve as a territorial warning to other males. A female's ability to chase other females off the territory signals the male that she's fit and healthy, too. No dancing necessary!
Q: I want to know if young robins "practice" their songs before they actually have to use them, or is the song something they just know when they need to know it?
A: Male robins start singing in late winter and early spring. There is no "practice" period in fall for this species. Individual robins each have unique elements in their song—notes and phrases that they came up with on their own, unlike song elements of their father and neighbors where they came from, and unlike song elements of the neighbors on their breeding grounds. But they also share song elements with other robins, especially their neighbors. This means that they do learn their song, but also invent their own identifying notes, and they start up this singing right when they need to.
Q: Robins live year-round in northern Virginia, through blizzards and freezing temperatures and I wonder: Why don't they migrate south?
A: It's likely that most of the robins from your area really have migrated south. But robins have no trouble whatsoever surviving freezing temperatures as long as they have food. Believe it or not, northern Virginia is a major winter destination for many robins from northern states and Canada. Many of the robins you see in winter came there specifically for the relatively balmy weather!
Q: I saw a solid white robin about a month ago and I am having people say it's not a robin. Can you comment?
A: Albinism and partial-albinism or "leucism" are more common, or at least more easily noticed by people, in robins than in most species. If your bird acted like a robin and was shaped like a robin, it almost definitely is a robin.