The Tadoussac Bird Observatory has been leading a research program on this little-known nocturnal raptor for more than 25 years. His work demonstrates the importance of monitoring the state of populations of wild species that bear witness to the health of Quebec’s forests.
It is dark in the dunes of Tadoussac and no artificial light allows you to find your way around the facilities of the Bird Observatory, which are nevertheless located very close. Only sounds that are unfamiliar to us, similar to repetitive “beeps”, break the ambient silence. Moreover, these are not natural songs, but rather recordings that serve to attract two species of nocturnal birds of prey that look like little owls: the Northern Saw-whet Owl and the Northern Saw-whet Owl.
These devices, which imitate the songs of the two species, are turned on every evening after dark, from the beginning of September to the end of October, to attract raptors to the nets which are stretched to catch them during their migration. autumnal. This leads them to pass in particular in this sector of the North Shore located along the St. Lawrence estuary.
This is also where the first program of its kind in Quebec was born, in 1996. “We have very little information on nocturnal birds of prey. Knowledge is essentially limited to nesting sites. This is also one of the elements that led to the creation of this project. And to create it, you had to ask yourself how to place the nets, which edges to use and when to do it. It’s not easy,” explains Alexandre Terrigeol, director of operations at the Tadoussac Bird Observatory (OOT).
Since then, every year, teams of researchers supported by volunteers spend cool evenings and cold nights capturing boreal owls. “We have few means to monitor the populations of these species. This is why a system of capture and baggage stations was developed in the 1980s in the United States. And when the project started in Tadoussac, we had so little data on the Saw-whet Owls that we thought their nesting in the boreal forest was anecdotal. But in the first year, there were more than 100 captures, which was very surprising, ”says Pascal Côté, who was director of the OOT from 2008 to 2021.
Information gathering
The formula, proven, is in fact a rigorous protocol which is designed to collect information “while minimizing the impacts” on the birds, which are obviously stressed by such an operation, underlines Laetitia Desbordes, manager of the migratory monitoring program for the birds. boreal owls.
According to what has been observed The duty while spending an evening there, the birds of prey, mostly female owls, are attracted by the songs broadcast and come and get caught in the nets. The team goes around these every 30 minutes, at most. When a boreal owl is found there, it is stripped, placed in a fabric pocket and transported to the OOT facilities, located a few dozen meters away.
This is where, while delicately handling the bird, we check its body condition, and therefore its corpulence, which remains modest. An adult owl barely weighs more than 100 grams (with the added bonus of a “big female” weighing 106 grams the evening of our visit).
By subsequently analyzing the pattern of moulting of the wing feathers, we can also obtain information on the age of each individual, which makes it possible to assess how many of the birds captured are young of the year, which gives an idea of reproductive success. In 2022, half of the approximately 300 Saw-whet Owls were young born in the previous months.
“It’s a good year, but that doesn’t mean that the population is doing well. We cannot draw this kind of conclusion ”, nuance Alexandre Terrigeol. The number of catches, year over year, also raises questions that researchers don’t yet have answers for. “Does climate change or logging influence the composition of forests, and therefore the abundance of food it needs? It’s hard to say. »
The OOT team also checks whether the bird already has a ring on its leg. In 2022, barely two raptors carried one, one captured in 2019 and another in 2021. “It allows us to verify the survival of these individuals and to be able to follow them”, specifies Alexandre Terrigeol. It must be said that the boreal owls that are banded in Tadoussac can also be recaptured elsewhere, for example at a research station in the United States. Their migrations can indeed bring them to different American states, and in particular as far south as Pennsylvania.
If the small raptor does not wear a ring, we measure its leg before installing one. Subsequently, each bird is brought to a small wooden shelf located in the middle of the trees, next to the trailer that serves as a refuge for researchers and volunteers. A photo is then taken, in order to offer the boreal owl for a symbolic “adoption” which in fact serves to finance research. “People who sponsor one can give it a name, and if it is recaptured, they are notified”, mentions the director of operations of the OOT.
Cash tracking
While commending the work of the volunteers who allow the follow-up project to materialize year after year, Pascal Côté deplores “the lack of funding” for this kind of research. “Financing a long-term wildlife monitoring project is extremely complicated. Governments are prepared to provide funding for five years, for example. But afterwards, it becomes very complex to obtain funds. To do it anyway, it takes a lot of willpower. And that’s important. To have quality data, you need long-term follow-up, so much more than five or ten years. »
Without long-term monitoring, we would have no idea of the health of the population, and therefore no possibility of assessing whether the species is in decline or not. If it is in decline, protection measures must be taken.
According to Alexandre Terrigeol, the relevance of the collection of information carried out for more than 25 years by the OOT is beyond doubt. “Long-term data, which is scarce, allows us to see what the abundance trends of species are. Is the trend up or down? Are there more juveniles? With long-term data, one can compare years. And we can group the data with other observatories, to check population trends on a North American scale. »
Same story on the side of the former director of the OOT. “Without the long-term surveys, we would have no idea of the health of the population, and therefore no possibility of assessing whether the species is in decline or not. If it is in decline, protection measures must be taken. He also points out that for other raptor species that nest in the boreal forest, the data are so limited that it is practically impossible to assess the “health” of the populations.
A finding that could call for greater efforts on the part of Quebec, not only for avian fauna, but for several other species whose situation remains relatively unknown. The government is also committed to respecting the global framework on biodiversity recently signed in Montreal. This plans to better protect natural environments, but also to curb the decline and extinction of fauna and flora.