From Finches to Ostriches: The Anatomy of a Museum Collection

From Finches to Ostriches: The Anatomy of a Museum Collection

By David Willard

Collection Manager, Birds

The other day, Peter Lowther from The Field Museum’s computer services department stopped by my office and handed me a frozen House Finch his 11-year-old daughter, Gloria, found dead in the snow by their house in Homewood, Ill. Although our computer records showed we already have more than 500 House Finches in the bird collection, I didn’t hesitate to accept another. After all, this was our first House Finch collected on Jan. 20, 1999. It is one of only four from Illinois, one of six from east of the Mississippi River and our only eastern specimen collected in winter.

It is also just one of the 425,000 specimens in our bird collection and one of 20 million specimens gathered from around the world that are housed in The Field Museum — in all, one of the largest and most important natural history and cultural collections in the world. When visitors enter the Museum, they encounter an extraordinary array of cultural artifacts, plants and animals. Most visitors don’t realize the specimens on exhibit represent only a fraction of those we have under lock and key in storage areas throughout the building. Why do we have so many specimens and why do we need more? Gloria’s House Finch can provide part of the answer.

Sixty years ago, a small number of House Finches from the Los Angeles area were released on Long Island, N.Y. For the next 30 years, the population grew slowly, until it suddenly exploded and began spreading up and down the East Coast and to the west. First recorded in Illinois in 1980, the House Finch is now one of the most conspicuous birds in suburban and urban areas of the Midwest. Gloria’s House Finch is a representative from the western frontier of the population’s expansion. By comparing this specimen to those collected from the East Coast 50 years ago and to those from the source population on the West Coast, we can begin to understand how animals change over time, or how they evolve.

Evolution is the central theme of many of the Museum’s exhibits and most of its research programs. The study of this process prompts Museum scientists to fan out over the globe to document the diversity of life on Earth. Like the research conducted in other areas of the Museum, the research of the bird division falls into two main categories — exploring remote areas and studying the specimens collected during these expeditions. The latter helps us better understand the patterns and processes of evolution and the conservation needs of the areas we study.

Collecting

The specimens used in museum studies come to us from a variety of sources. Universities often donate their collections when they no longer have the staff to study and care for them. Birds that die in zoos, birds hit by cars and the more than 2,000 birds that crash into glass windows each year in Chicago all augment the Museum’s bird collections.

However, the specimens we obtain from these sources represent only a small percentage of the bird species in the world. Searching for the rest of them often takes us to pristine outposts where there is little available information about the region’s natural history. In the past 10 years, staff and students from the bird division have worked in Madagascar, Uganda, South Africa, Gabon, the Philippines, Mexico, Peru, Bolivia, Brazil and Australia. We have described previously unknown features of the birds in these areas by watching them through binoculars. We also have recorded their songs and collected some of them for our own studies and for studies by future generations.

While we occasionally have the luxury of modern technology, such as airplanes for reconnaissance, our collection strategies aren’t much different from those of earlier generations. We still camp for weeks on end, and we still have to work our way up trailless mountains in order to study the birds at the top. Like those that came before us, we still carry our supplies on our backs and we still pay our dues in tropical diseases like malaria, leishmaniasis and dengue fever. But for all of us who grew up loving wild places, the thrill of discovery on these expeditions is unparalleled.

On an expedition to the Andes of Peru, we found the Peruvian Piedtail, a hummingbird thought to be extremely rare — everything known about it was written on labels attached to a few old museum specimens. It turned out to be a common bird, but only in a very narrow elevation band, above and below which it was absent. Its presumed rarity simply reflected a lack of exploration in the appropriate places. In the heart of a swamp in the Impenetrable Forest of Uganda, we found several birds that no other scientist had ever documented in this region, despite more than a century of intense exploration. Again, no one had ventured into the waist-high water of the swamp to see what was there.

We also have had the extraordinary luck of finding some species that are new to science. While an entomologist may go into the field expecting to find new insects (because there are so many insects and so few entomologists), it is much rarer for an ornithologist to find something new. Back in the 1980s, a group of ornithologists and mammalogists from the Museum mounted an expedition to Rondônia in southwestern Brazil. We set up fine-meshed, almost invisible mist nets to capture birds that are difficult to observe in the forest understory. While removing and measuring familiar bird after familiar bird from the nets one morning, I came upon one that was totally unfamiliar. It was a chunky, thrush-sized bird, cinnamon colored with a black throat patch. Its most surprising feature was its bill, which had a pronounced upward curve and was flat on either side like a knife blade. Nothing like it had ever been described and the only bird that even closely resembled it lives 1,300 miles away in the northern Andes of Colombia. We later named the new species the Rondonia Bushbird.

Expeditions to northern Peru in the 1970s produced an astounding four new species from a single mountain range: the Bar-winged Wood-Wren; the Royal Sunangel; Peterson’s Screech-Owl; and the Cinnamon-breasted Tody-Tyrant. Similar explorations in southern Peru during the 1980s led to the discovery of the Manu Antbird and the Cinnamon-faced Tyrannulet.

These expeditions have produced collections that contribute to our basic knowledge of bird biology and diversity and provide information upon which conservation biologists base many of their decisions. They also follow a tradition that dates to the Museum’s inception. In the 1890s, D.G. Elliot, the division’s first curator, made one of the first ornithological expeditions to Somalia. His successor, Charles Cory, was a pioneer in Egyptian ornithology who also hired collectors to bring back some of the first bird specimens from the West Indies. Ever since, Museum researchers have studied these collections and added to them through their own expeditions.

Research

The early explorers were concerned with two primary features of bird biology — what kinds of birds existed and where they lived. The typical label accompanying their specimens contains the name of the place where they found the bird and a date. On their return to the Museum, they lined up their specimens next to those already in the collection; if a new specimen from the Peruvian Andes differed even slightly from something similar in the Colombian Andes, they identified it as a new species or subspecies and gave it a new name.

For much of the Museum’s history, scientists were committed to describing diversity, which remains an important feature of contemporary ornithological work. As interests broadened, however, researchers noted additional information, to the point where a specimen label today also includes the bird’s weight, breeding condition, stomach contents, a description of its habitat and the colors of its eyes, bills and legs. With refined techniques for generating and analyzing molecular data, we also save tissue from specimens for genetic studies.

Added to the basic work of describing diversity is an ever-increasing attempt to explain it. The research of Shannon Hackett, head of the bird division, is an example of this next order of questions we are asking today. One of Hackett’s projects concerns manakins, a family of birds with brightly colored red, yellow and blue feathers highlighted against ebony blacks and glistening greens. But some of these birds are drab brown. Many manakins have elaborate courtship displays, with males gathering on traditional dancing grounds called leks to show off their finery to females that make a choice of mate based on some manakin perception of a male’s charm. But some manakins have no fancy courtship displays. It is easy to sit back with trays of manakin specimens spread out on counters and speculate that the colorful species evolved from drab ones, or that complicated courtship displays must have evolved from simple ones. While this speculation helps formulate a series of questions, the answers require independent tests.

Using specimens collected on her expeditions, along with additional ones provided by other museums, Hackett looks at manakin DNA as her independent test. When she is finished with her analyses, she will produce a phylogeny of the manakins — a branching tree showing the relationships of all of the varieties. On this tree, she can superimpose the plumage characteristics and courtship intricacies in order to understand the evolution of the patterns that prompted so much initial speculation. Her results can help us understand where and from what ancestors manakins originated, how they spread throughout their current geographic range and what factors led to their separation into the more than 50 species recognized today.

When we know the answers to these questions for a group like manakins, we can compare them with other South American bird families to see whether the results can be generalized, or whether they are unique to manakins. When we understand avian diversity in South America, we can compare the patterns there with those in Africa and Asia, continents with very different geological histories. Gradually, as scientists compare ornithological studies to studies of other zoological groups and of botany and paleontology, we start to understand how life on this planet evolved.

Just as Hackett needed to borrow specimens from other museums to make her studies complete, the Museum’s bird division lends several thousand specimens every year to scientists working on projects at other institutions. Almost every ornithological journal contains at least one article in each issue where the authors relied on our collections for their conclusions.

At the moment, scientists from the Museum of Natural History and Science in Cincinnati are using Field Museum specimens from the Philippines to describe a new sunbird species and researchers at the Muséum National d’Histoire Naturelle in Paris are studying bird tissue from our Madagascar collection to determine whether they have discovered a new family of birds. In addition, ornithologists at the Smithsonian Institution are developing a field guide to the birds of India and Pakistan based in part on our collections. And soon, we will be sending feathers from rare heron specimens to Louisiana State University and scrapings from the foot pads of Asian eagle specimens to Austria, where scientists have learned to extract DNA from old specimens.

Researchers also come to the Museum to do their work. Recent visitors include a professor from the University of Wisconsin who is studying relationships among hummingbirds, and a graduate student from Yale who is comparing our skeletons of seriemas (large, ground-walking birds from the pampas of South America) with some fossilized birds she recently discovered. An archaeologist from Michigan State is using our collection to identify fragments of bird bones she unearthed at an excavation site in Israel. This month, a Colombian conservation biologist will use the collections to establish baseline information on bird distributions for use in land-management programs back home. These activities are just a sampling of those in one division of five in the zoology department, which in turn is only one of four scientific departments at the Museum (zoology, geology, botany and anthropology).

While we make and maintain collections of birds for scientific study, scientists are not the only ones who use them. Working next to these scientists is a wood carver from Indiana who is sketching, painting and taking notes on the dimensions of a Painted Bunting to try to make his finished sculpture as accurate as possible. Each semester, students from the Art Institute visit the Museum to study research specimens of birds they drew at the zoo. This allows them to add details to their drawings that would be impossible to capture without a close-up view of their subject. In addition, bird watchers come here to hone their identification skills, to check that the Baird’s Sparrow they thought they saw was not just an odd Savannah Sparrow, or to learn the differences between Greater and Lesser Scaups. Even law enforcement gets into the act. If a traveler brings home a souvenir with a feather on it or a company imports merchandise with feathers, the U.S. Fish and Wildlife Service brings the items to the Museum to determine whether the feathers came from protected species. Currently, the Palatine police are relying on our collections for help in interpreting evidence in an unsolved murder case.

The Big Picture

So, the House Finch that Gloria had the foresight to pick up and give to her father can serve a variety of purposes. An artist who is struck by the beauty of a House Finch at a bird feeder can come here and paint from the specimen. A birder who is unsure of the differences between House and Purple Finches can solve that problem by comparing specimens of the two species. And a scientist wanting to understand the evolutionary history of the House Finch can study Gloria’s bird in the context of the 530 other House Finch specimens housed at The Field Museum — specimens that span the past 100 years and that were collected throughout North America. Each additional specimen we add to our collections allows us to fine-tune our questions and to understand the biological world in greater detail. Gloria’s House Finch joins nearly half a million other bird specimens from across the world, representing most of its bird species. If we maintain these collections well and build upon them, they will continue to serve their current functions, as well as to help our descendants answer questions we haven’t even thought to ask.

This article was originally published in the March/April 1999, In The Field.