Ecology of Yellow-bellied Sapsuckers
About the Project
The yellow-bellied sapsucker (Sphyrapicus varius), is a common bird in the hardwood and mixed wood forests of Eastern Canada. It is a cavity nester, creating nests in snags or trees with heart rot. These cavities are often later used by other species of cavity dwellers. Sapsuckers also create holes through the bark of deciduous trees to access the nutrient rich sap, again providing other species a service in terms of access to this nutrient rich food source. In addition to nesting cavity trees and sapwell trees, sapsuckers also require trees to hunt for insects, another main food source. Having an obviously high reliance on forest composition, it is important to understand how logging affects the ecology of this important bird species. By banding and aging 165 birds over two years, and locating over 300 nests, the success of sapsuckers in different forest and harvesting types can be examined.
Several main research findings include;
- The higher suitability of heart-rotted trees such as beech for nesting
- If these trees are not available, they may select others which are soft and easy to excavate
- In this softer wood, nest predation by black bears is much higher
- However, they appear to learn quickly and will switch territories to increase nesting success ( a phenomenon not previously observed for this migrating bird species)
- On the other hand, birds that successfully nest one year will almost always stay in the same territory, although 40% of them switched trees
- Nesting success and survivorship is highest in aspen and maple-beech forests not logged for the past 60 years or more
- This may be due to more suitable nesting trees, as well as less overall distance to travel for suitable feeding trees
This research highlights the importance of selection logging to leave good nesting habitat, rather than removing trees with heart rot to improve stand composition for harvest. It is also interesting that sapsuckers seem to use their previous experiences in the selection of nests. This implies that bear predation may be a threat the sapsuckers have not previously encountered, so they do not have a programmed response.