Ruminations

Hummingbird Decline

"No one has ever measured pesticides in hummingbirds before. So we decided to try it. It turns out, to our surprise actually, that the birds are obviously picking up pesticides in their food, which can be nectar and also insects."
"Now what does it mean? Right now we're just understanding what the level of exposure is, and then how is it affecting the [hummingbird] population."
Christine Bishop, biologist, Environment and Climate Change Canada

Christine Bishop, a research scientist with Environment and Climate Change Canada, holds a rufous juvenile male hummingbird as she prepares to measure and band it and collect urine and feces for testing, in Surrey, B.C. (Darryl Dyck/Canadian Press)

Research scientist in British Columbia, Christine Bishop, is attempting to determine why it is that some species of North American hummingbirds appear to be in severe decline. A preliminary finding is that the cause may possibly be related to the very same insecticide used in agriculture that is affecting the honey bee population. She and other researchers have begun studying a number of factors ranging from habitat loss to alterations in plant bloom time, that may be involved.

And the method these researchers decided to rely upon from which to extract their data is the collection of urine and feces from the hummingbirds. That collection and the resulting data appear to confirm that the concentration of pesticides in hummingbird urine is fairly high, at three parts per billion. The study focused on the Fraser Valley and southern British Columbia, those agricultural regions identified as a core locale for the rufous hummingbird.

The tiny bird with a red throat has a negligible weight, roughly that of a five-cent piece. It spends its summers in British Columbia, in Alaska and the Pacific Northwest states. When signs of winter arriving alert the hummingbird to its survival imperative by reverting to its species' habitual migration, it returns to the southern United States and Mexico which represent its winter habitation site, away from the bitter cold of the summer location.

A rufous juvenile male hummingbird flies around after being captured with a net above a feeder. (Darryl Dyck/Canadian Press)

To obtain the feces and urine of those flighty, ever-moving tiny birds, the researchers place nets over feeders which are lowered when a hummingbird comes along to feed. As a byproduct of the hummingbird's constant processing of nectar, it concomitantly expels it so that the collection of urine and feces for test results is then accomplished with the help of the nets. This study is meant to last for five years, and is only in its initial stage, at two years.

Hummingbirds, like bees, habitually come back to routinely recognized places to find their food, recalling where certain flowers grow. Another concern is that pesticide absorption might have the effect of disrupting their memory. According to an annual breeding bird survey, between 1966 and 2013, the population on the Pacific Coast of the rufous hummingbird has declined an average of 2.67 percent annually.

Two other species of hummingbird were also found to be in decline, the Allen's and broad-tailed hummingbirds, leading Health Canada to reevaluate the use of imidacloprid, a neonicotinoid insecticides commonly used on agricultural crops and coincidentally used as well for flea and tick control on cats and dogs. Separately, an earlier Health Canada report noted that imidacloprid has the potential to exact short- and long-term effects on bees inclusive of behavioral changes and mortality rates.

Aside from suspicions about the effect of these insecticides there are additional issues which may be impacting on the well-being of both hummingbirds and bees. Habitat loss, seasonal plants blooming at a different time of season, even an increase in the deer population, consuming the same flowers required by the hummingbirds to exist, could all be found to play a role in the decline of these wonderful, tiny birds.