Many of those using the Visitor Centre at Montrose Basin are local people with an interest in wildlife and a rich knowledge of the flora and fauna of Angus.
Many others are holiday makers, ranging from experienced birdwatchers, who have included Montrose Basin on their itinerary of interesting Scottish locations, to families who are simply seeking shelter and something to amuse the children on a rainy day.
One of the joys of working in the centre is the opportunity to chat and to learn from this endlessly fascinating range of people. The experts are almost always very happy to share their knowledge and experiences with staff and with other visitors. However, it is those who are just beginning to learn about wildlife who often ask apparently simple questions which on further reflection reveal some of the gaps in our knowledge about wildlife.
Someone recently asked why there were so few grey herons on the basin when they had seen so many more on a visit earlier in the year. It was explained that herons usually nest in colonies known as heronries and that the breeding birds had moved to those breeding areas.
This then prompted the question of what advantages exist from colonial nesting. The received wisdom is that birds have evolved this behaviour to fend off potential predators and to learn from each other where there are good food supplies. Scientists have disagreed about which of these two factors is most important but most would accept both as being significant.
We can see these advantages in action from the centre, when we watch terns mobbing potential predators which approach the tern raft and as the terns follow each other out to sea in search of sand eels. Similar behaviour can be witnessed when watching the vast breeding colonies of razorbills, guillemots and kittiwakes on the cliffs south of Stonehaven.
These behaviours are not so readily apparent with grey herons probably because predation pressures are very low and also because new heronries tend to be established near suitable foraging sites. So with grey herons, the advantages of colonial nesting are not as clear as with many other species.
At this time of year returning visitors also notice a reduction in the number of common waders. Many oystercatchers, curlews, redshanks and lapwings have moved further inland, not to colonies, but as breeding pairs. The grazing land in the Angus glens echoes to the calls of these familiar species during the summer. In a few weeks' time, if you are patient and keep your distance, you will see the flightless chicks scurrying after the adult birds.
The combination of migration and these relatively short distance dispersals mean that the population around the basin is constantly changing and there is scarcely any time of year when we are not keenly anticipating the return of a particular species or noting the absence of recently common birds.
My favourite question of the past few weeks did not occur at the visitor centre but on a visit to a school to demonstrate bird ringing techniques. One of the nursery class pupils, clearly entranced by a close up encounter with a brightly plumed blue tit, wanted to know if that particular bird would turn into a butterfly. The idea was so enchanting and imaginative that I longed to say yes, but the need to provide the facts won the day.