You've got to be nuts!Geoffrey Dabb
As regular Red-tail news readers will know, seeds from the nuts or seed capsules of two stringybark eucalypts, Brown Stringybark (Eucalyptus baxteri) and Desert Stringybark (Eucalyptus arenacea) are the main year-round food of our Red-tails.
In summer during good Buloke seasons, many birds will switch to Buloke cones, extracting the seeds for the few months they remain in the cone. Stringybark seeds can remain in their capsules for two or more years and provide food for all that time. However, Red-tails are quite fussy about the stringybark trees they feed in, preferring larger trees with more capsules, and preferring capsules that are less than 12 months since they first matured. Red-tails are highly nomadic, moving across their range seeking out these preferred seed sources.
Every year we count these stringybark nuts for several reasons. One is to get an idea of how much food there is for Red-tails in that year, another is to track the relationship between breeding success and food availability. A third is to identify any areas planned for fuel-reduction burning which have higher seed crops. We try and get those burns deferred for a year until the seed crop ages and therefore become less suitable for Red-tails.
This year we’ve been reviewing these data, and at the same time Dani, our PhD student has been counting nuts around nests where she has auditory recorders. We use binoculars to scan each tree and estimate the density of nuts across the tree, as well as the age of the nuts. We’ve had to do more this year, because we are evaluating the method we use, to make sure it is telling us what we need to know. We’ve counted and counted until we literally have been going nuts. Not to mention the nasty crick in the neck! Our results will help us better understand how Red-tails are influenced by stringybark seed production, which in turn, means we have more confidence in what we are doing to protect Red-tails.
- Image: Luke Leddy
Feb 14, 2014