Many of my students are now trying their hands at blogging a peer reviewed paper. This is Amy Wray’s look at a new paper on hummingbirds:
Helping the Hummingbird: Why a Tiny Bird Deserves Big Research Efforts
A few years ago I had an awesome opportunity to work as a summer intern at a wildlife rehabilitation center. Lots of animals came through the center while I was there – squirrels, raccoons, possums, fawns, and skunks to name a few – but there was one tiny creature in particular who left a huge impression. He was an orphaned Anna’s hummingbird, small but spunky and ever so charming. One of my tasks was to help this hummingbird practice his flying skills. He would flutter about for a little while, and I would follow him around. At the slightest sign that he was growing weary, my job was to offer an index finger as a place to rest. Before this adorable but anxiety-inducing experience, I had never seen a hummingbird up so close. Like most people, I usually saw them whizzing around, hovering briefly at a flower before darting quickly away. But when this tired little guy was perching on my finger – so light that I could barely feel his weight – it struck me that hummingbirds, for all their ubiquity, were actually fairly elusive creatures.
By the end of the summer that particular hummingbird felt like he was part of my family, but taxonomically speaking the hummingbird actually belongs to the family Trochilidae. There are many species of hummingbird, with ranges that span from Alaska to Argentina. Although they are an interesting and charismatic animals, there have not been many studies dedicated to understanding their health and the effects of disease conditions on their populations.
A recent publication by Godoy et al. in the Journal of Ornithology thoroughly reviews the existing literature on hummingbird health (2014). The authors of this paper, a research group at the University of California, Davis*, advocate for the importance of studying hummingbirds due to their unique physiology, behavior, and ecology. Hummingbirds are unique in many ways, even in comparison to other birds. These tiny animals have an extremely high metabolic rate, and they have to constantly take in calories in order to support the amount of energy they expend. This means that if their food source – the flowers from which they drink nectar – becomes scarce, hummingbirds can be in real trouble. The loss of these food sources can be caused or exacerbated by habitat loss and urbanization. On top of all of this, agricultural pesticide use was also found to be a likely cause of population decline in at least one hummingbird species, yet it remains unknown whether and to what extent pesticides pose a threat to others.
In a population that is already struggling, a potential disease outbreak could have devastating effects especially if these birds are undernourished or stressed. Hummingbirds have been known to be afflicted by diseases such as West Nile Virus, Avian pox virus, Chlamydia bacteria, and many others which are outlined by Godoy et al. in their research paper. The authors emphasize that the extent to which disease conditions affect hummingbird populations is not well known. Hummingbirds are not often chosen as the subject of disease research in comparison to other birds, in part because their small size makes them difficult to capture, handle, and even observe. However, the difficulties associated with research on hummingbirds may be worth overcoming if disease conditions pose a significant threat to their populations.
Protecting hummingbirds need not be an entirely selfless endeavor – the health of their populations can actually help us humans know if our own environment is healthy. Godoy et al. suggest that hummingbirds could be potentially useful as a “sentinel” – an animal that detects environmental hazards. Some hummingbird species could be particularly useful because they have adapted to the urban environments, which means that they are exposed to many of the same pathogens to which humans are exposed. Therefore, discovering disease conditions in hummingbird populations might reveal factors that also put human health at risk. Additionally because hummingbirds have many characteristics that make them different from other bird species, they may not have the same disease risks. This means that studying hummingbird health could reveal different environmental hazards than those that would be signaled by other types of birds.
Returning to the story of my hummingbird friend at the wildlife rehabilitation center – eventually he got so good at flying that he no longer needed any assistance, and was released back into the wild habitat of Piedmont, California. While I hope he is still happily buzzing around the flower buffets of suburbia, with his iridescent feathers glimmering in the sunshine (hummingbirds can live for up to 10 years!), the fate of other hummingbirds and the populations they belong to may not be so secure. Nonetheless, by contributing a greater effort to learning about these animals, we will know more about how to help improve both hummingbird and human health.
Godoy, L. A., Tell, L. A., & Ernest, H. B. (2014). Hummingbird health: pathogens and disease conditions in the family Trochilidae. Journal of Ornithology, 155(1), 1-12.
* The lead author of this paper Loreto Godoy was a Ph.D. student at UC Davis. She was tragically killed in a car crash in June of 2013. Thus this is a posthumous publication. Her lab group is trying to establish a scholarship in her honor. Please consider donating here -JAD