Working on the Montrose Basin local nature reserve, I am privileged to witness on a daily basis the ways in which wildlife adapts to the various challenges it faces.
Seasonality of course has a major impact on wildlife, dictating when the time is right for hibernation, migration, or breeding. Montrose Basin is possibly most well known for its avian interest and the variation in species that visit the reserve during different times of the year.
On June 19, 55 female Goosander were seen on the basin from the visitor centre. They appeared to be feeding in a group, but the sighting raised the question of why the flock of entirely female Goosander was on the reserve. In May and June, adult males gather to migrate to Northern Scandinavia to moult, not returning to Scotland until late October, leaving the females behind to care for the brood.
In June, any females whose nests have failed will gather together and form protective flocks to moult. The female Goosander will not travel as far as the male to moult and the estuary at Montrose offers an ideal site.
Moulting birds require large expanses of water for protection from predators as, along with their flight feathers, they lose the ability to fly for about a month before feathers are replaced. The reserve also offers an abundance of fish, providing the Goosander with lots of much needed energy for this process.
It’s not just Goosander that have begun their seasonal moult. Male Eider have been seen from the visitor centre forming flocks for their moult where they go through what is known as ‘eclipse plumage’ – losing their striking appearance to assist in camouflage during this flightless time. Again the females are left to incubate eggs and raise ducklings. Communal crèches are formed, allowing Eider to take turns in caring for the broods whilst regaining condition from a period of starvation during incubation.
For Goosander and Eider alike, the Montrose Basin is an ideal food source. While Eider migrate to breed on the reserve Female Goosander arrive here after breeding to take advantage of the abundance of fish and safety of the expanse of the estuary, but not all birds adapt to seasonal changes by migrating. I recently saw a Bearded Tit in reedbeds to the East of the reserve. This amber listed bird is a fairly rare sighting around the basin.
At this time of year, the reedbeds are used as foraging grounds for invertebrates which offer a high source of protein. Bearded Tit stay close to their breeding grounds during winter months, and adapt to the lack of availability of invertebrates by completely altering their digestive systems. This very unusual adaptation to variation in food availability between seasons is achieved by the stomach developing hard plates and the bird eating numerous amounts of small stones. This gravel means that the Bearded Tit will be able to digest seeds through the winter months so there is no need to migrate and follow a food source.
This demonstrates a way in which the reserve provides fantastic habitat for such a variety of birds during different seasons. Visitors to the reserve will have lots to enjoy at this time of year and if you are interested in seeing ducks in moult, or Eider crèches. I recommend you do so soon!
There are plenty of activities going on to keep children entertained in July with ‘ Bugs and slugs’ on the 11th, ‘Art attack’ on the 18th and ‘Mud glorious mud!’ on the 25th. For details, or to book a place please call the visitor centre on 01674 676 336, or e-mail email@example.com.
SWT Montrose Basin ranger