Step 4 Birch Bark Canoe

A recent web-based discussion about the identification of an odd-coloured bluebird reminded me of a similar odd bluebird in the Museum collections. There are three bluebird species in North America: Eastern, Western, and Mountain. Contrary to what one might expect from their names, Manitoba is home to the Eastern and Mountain Bluebird, the Western being found in Canada only on the other side of the Rockies from us.

What does this have to do with Museum collections? Because of that amazing variation, the specimens held in a museum are very useful for comparison and the museum collections themselves are a good place to deposit unusual specimens that might need a harder look later. Bluebirds are a good case in point. In the late 1960’s, an ardent bluebird worker in Manitoba, John Lane, found a very strange-looking male bird at one of his nest boxes. Its coloration suggested a hybrid between an Eastern and a Mountain Bluebird. Hybrids among bluebirds were not known at this time, and this was rare enough that he got in contact with the Museum and the unusual step was taken to collect the apparent hybrid, its Mountain Bluebird mate, and raise the young in captivity (for more details, see an article by John Lane in The Blue Jay, 1969, pages 18-21).

The hybrid male bird is certainly strangely-coloured. It has the quality of blue of an Eastern Bluebird, but rather than the typical rusty-orange throat and breast of this species, these areas are mostly blue, similar to the pattern of a male Mountain Bluebird. There are, however, some dashes of reddish mixed in. A look at the back shows the difference in blue colour of the Mountain Bluebird and the possible hybrid and Eastern birds.

The bluebird species also vary in size, although with overlap. Once the potential hybrid was at the Museum, measurements could be made to see where it might fit. As an example, wing length (measured officially as ‘wing chord’) for male Easterns ranges from 95-105 mm and for male Mountains ranges from 108-121 mm. The hybrid’s wing length, at 104.5 mm is at the high end of Eastern, but nowhere near the Mountain Bluebird size range. This same pattern holds for other measurements.

One possibility not considered by Lane is that the odd-coloured bluebird might be a hybrid of Western and Mountain. Western Bluebirds have a blue throat with an orange breast, and are slightly larger than Eastern Bluebirds, making the measurements fit that species. The blue breast of the hybrid would be the possible Mountain parent contribution. One issue with this is that Western Bluebirds usually have a rusty-orange patch on their shoulder or back, absent on the possible hybrid.

There is one more way that the hybridization question might be resolved with the Museum specimen. Dried skins, like these birds, can provide samples of DNA, the molecules that are the instructions for building and operating living things. Just as human DNA samples can identify a particular person or determine to whom they are related, animal DNA can be used to identify parentage. Perhaps a biologist interested in bluebirds will one day run a sample of DNA and help to solve which species might have hybridized to make our strange specimen.

But without the specimen in a museum collection, we would never have the chance to check.

We recently received a request for a few feathers off of a single specimen of Ivory Gull (Pagophila eburnea) collected north of The Pas in 1926, the only specimen we have of this species. The Ivory Gull is a High Arctic breeder that has made an appearance in Manitoba only about a dozen times in the last 100 years. The species is listed as Endangered in Canada and its populations are declining. A research group is examining levels of mercury and stable isotopes of carbon and nitrogen in feathers to investigate the possible role of heavy metal contamination and changes in foraging behaviour in Ivory Gull decline. The Manitoba Museum specimen is one of only about 150 specimens from Canada in all the museums of North America, and its age makes it particularly valuable for reconstructing historic levels of contamination and isotopes. Who could have predicted the value of this Museum specimen for conservation of the species when it was collected those many years ago?

By sharing information on Museum rarities with researchers who can pool data from the few specimens available in collections from around the world, we learn more about the biology of the organism, making the specimen more ‘valuable’ in terms of information and helping conservation efforts. The Museum ends up with another story to tell about its collection and about the animals themselves. Science, the Museum, and, most importantly, the animal will all win from this exchange.

Nature generally can be understood through patterns. Unique observations, like a rare gull found north of The Pas in 1926, are curiosities, but can’t contribute very much to the bigger picture as an isolated event. Even the proverbial apple clunking onto Newton’s head, though important as a unique event, only becomes truly valuable when its act of falling towards Earth can be generalized to explain why other things also fall.

This helps to explain why the Museum has, when possible, more than one example of a species, and continues to grow collections through active collecting. Just as a single letter is more as a part of a word, or a word is more meaningful when put into a sentence, a specimen becomes more in the context of a collection. A particular specimen does have value in and of itself as a record of occurrence in a single place at a single moment (called a voucher), or sometimes even has monetary value. But several specimens from different places collected at different times provide a more complete story of species variability, distribution, biology, and, as in the case of Ivory Gull mercury levels, how these might have changed over time and space. Each individual provides a data point, and an important one, but the real value comes from the collection as a whole. And a new specimen added to the collection today, while not necessarily individually significant right now, might be so 100 years from now, just as the Ivory Gull specimen collected in 1926 is valuable today.

Richard Fortey (a paleontologist at The Natural History Museum, London) suggested that natural history museums are the archives of the Earth, an apt metaphor. Through their collections, museums document individual “events” as specimens, which together tell the story of how our natural world changes over time. The Manitoba Museum plays this critical role as natural history archive for the province. Specimens old and new are together a feather in our collective cap.