the Walnut Diary

I’ve always thought of the male American robin as a drab, persistent and boringly family-oriented bird, but it turns out that a great deal of his compulsive activity may be the result of pretty orange plumage and that distinctive egg colour.

Saturday I helped Philina English disassemble a net she had used to trap the robin who had laid her eggs in our barn. She disconnected the hair-thin web, spun it into a rope, and then stuffed it into a bag, lightweight poles still attached.

The robin had found herself cached in a soft, dark bag in the back of a van full of lab equipment while Philina examined each egg with a spectrometer attached to a laptop to determine its colour, and then entered a wide range of data pertaining to the egg’s age, mass, and fertility. Undergraduate student Fraser Cameron dutifully wrote down each item muttered to him by the pair of Queen’s graduate students.

While we worked on the net Lori Parker collected blood samples and breast feathers from the bird for the plumage study and D.N.A. tests. Then they tagged her and let her go.

A graduate student from Portland, Susie Crowe originally located the nests on the farm for the study and will assist with the sampling. The crew plans to gather data on about a hundred robins over the summer, establishing family trees through D.N.A. testing and seeking to develop information on the relationship between egg and plumage colour and breeding success.

Family trees of robin chicks show that the males from neighboring nests routinely father one or two of the hatchlings. Robins mate socially, sharing chick-rearing duties, but apparently aren’t adverse to occasional casts outside the gene pool. English refused to see this as a sensational bit of gossip from the hedgerows. From her point of view, it’s just another evolutionary device the species has developed.

Lori told me that only the female robins incubate the eggs. Apart from fertilization duties, after building the nest the male partner doesn’t go to work again until the feeding stage, and the bulk of the team’s research deals with attempts to quantify the signals which bond the male parent to the clutch of eggs so that he will put a significant effort into rearing the young. Once the chicks hatch, the crew will film two-hour blocks during feeding times to determine the male parent’s involvement and attempt to correlate this investment with egg colour and the brilliance of the mother’s plumage.

Philina even showed me some fake eggs, both strongly-coloured and faded, which they plan to secrete into selected nests. She hopes the variations in the colour of the eggs will enable them to determine the extent to which the male’s memory of the nest picture drives him to provide for the chicks.

I noticed that when the crew had removed the eggs for study they were careful to cover the empty nest. Lori explained that under no conditions could they allow the male to see an empty nest, because then he would abandon the whole project.

A day later the mother robin was back on her nest, still making a ruckus loud enough to startle the resident skunk every time anyone went near her nest. She seems no worse from her session with the crew yesterday.

The second test subject was a little less co-operative. Nesting in a stunted apple tree in the horse pasture, this bird carefully avoided their nets in early afternoon Saturday, then wandered off to feed and play with the other robins until the crew had moved elsewhere. Sunday morning when Lori and Fraser returned, she waited until they had the nets set up, then flew between them and away. Their respect for this “clever girl” grows with each capture attempt.

All of this activity seeks to answer the question: “Why is a robin’s egg blue?” English suggested that this study might at first seem frivolous insofar as it has no immediate conservation benefit, but ultimately it’s human to wonder about subjects like this, and graduate students strive to provide answers.

The advent of the inexpensive spectrometer has opened new doors for research on colour, suggested Roslyn Dakin, another member of the Montgomerie Research Group at Queen’s.

This study will continue throughout the summer at the Croskery farm, Chaffey’s Locks and Newboro, as well as at locations nearer to Kingston.

If you’d like to offer access to robin’s nests on your property to this very amiable crew, drop an email to Lori Parker at the address below.

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Email 6pae1@queensu.ca or call 613-547-9096 along with:

1) your name and contact information

2) name and contact information for property owner (if known)

3) directions based on street/road addresses OR GPS coordinates of the nest

4) description of nesting stage (under construction, eggs seen etc.)

5) if available, photographs of nest location (not necessarily the nest itself)