By March, I am already scanning the skies on the off chance of an early Swallow passing over, and when I see the first arrival I am always overjoyed and can't wait to see groups of them gathering on the wires, hawking for insects over the fields and twisting and turning with speed and agility around the farm buildings.

My earliest ever Swallows were two years ago, on a blistery late February morning at the RSPB Goldcliff Reserve, where stood at the seawall two Swallows came past heading towards The Point, hugging the seawall as they passed. I remember saying to my friend, can you imagine their conversation? ‘why on earth did we come over now’?

In Victorian times there was the belief that Swallows hibernated for the winter at the base of the reeds in the mud and re-emerged in the spring. We laugh at this notion now that we know through science and ornithology that they migrate to Africa in September and return here around the end of March or early April. But when you think about it, it may well have seemed like that back then.

Remember that they had very little in the way of optical equipment, no bird guides and certainly no tracking apps or social media to report sightings. In fact, Swallows will roost in reedbeds and in very large numbers prior to migrating, and when you consider they would have gathered by early evening but be gone by first light the following morning, no wonder it seemed they had simply gone into the mud to hibernate.

 Gwent Wildlife Trust has a number of reserves where Swallows flourish both from adequate nesting sites and an abundance of insects from well managed reserves, and both RSPB's Goldcliff near Newport and Gwent Wildlife Trust's Magor Marsh are strongholds. I have many fond memories at Goldcliff watching large groups suddenly appear as if from nowhere to ‘hawk’ for insects over the lagoons and the surrounding fields. Reserves such as Goldcliff have small herds of cattle as part of the ‘commoners’ grazing rights to feed on the reserve to help keep the vegetation down. Such animals attract insects, and these can be easily picked off by the skillful hunting of the Swallow.

On occasion, the reeds at Magor Marsh can see Swallows gathering on them and the reeds will actually bend over at times under the weight of several birds along its stems. Such reserves and others like GWT's Henllys Bog along with great feeding areas, all have one thing in common, surrounding farmland, and where there is farmland there are farms and outbuildings – ideal nesting sites, and where they are also known by many as ‘Barn Swallows’.

Every farmer I have ever spoken to has said they love to see the Swallows back and nesting, and can never get over how they can make such a long journey. Like all of us, they are also impressed when a bird born in their barn the one year will return to the same barn the next – now how on earth can it make such a remarkable journey, surely not by memory alone? The debate on that one will go on for many, many years yet.

The Barn Swallow (Hirundo rustica) is the most widespread species of swallow in the world. The song is a cheerful warble ending with a ‘suseer’. The second note is higher than the first and falls in pitch. Calls generally include a ‘witt’ or ‘witt-witt’ and a loud ‘splee’ when excited or alarmed by intruders close to the nest. The alarm calls are quite distinctive, including a sharp ‘siffitt’ for cats and predators such as birds of prey see an alarm call of ‘flitt flitt’.  Hirundo is the Latin word for ‘swallow’ and rustica means ‘of the country’.  As its name implies, the Barn Swallow typically nests inside accessible buildings such as barns and stables, or under bridges, but before man-made sites became common, they nested on cliff faces or in caves, but this is now rare.

The amount of food a clutch will get depends on the size of the clutch. Larger clutches get more food on average. The timing of a clutch also determines the food given and later broods get food that is smaller in size compared to earlier broods. This is because larger insects can be too far away from the nest to warrant using energy to find them. Males with long tail streamers also have larger white tail spots, and since feather-eating bird lice prefer white feathers, large white tail spots without parasite damage demonstrate a healthy bird. A neat cup shaped nest is constructed placed against a beam or a suitable vertical position and is constructed by both sexes. Mud pellets are collected in their beaks so if you can provide a muddy area at the edge of a pool or pond. The nest will be lined with feathers, grasses, algae and other soft materials. If a male is a better nest builder, the female will lay more eggs.  Hatching success is 90% and the fledging survival rate is 70–90%. Average mortality is 70–80%.  Although the record age is more than 11 years, most survive less than four years.

Occasionally Swallows will nest in a house porch and sometimes this is discouraged by the owner as the young deposit a lot of droppings on the steps. I always tell people to put a small temporary wooden shelf under the nest to catch the majority of the droppings and I also gently remind people that it is illegal to disturb nesting birds or destroy nests (Wildlife and Countryside Act 1981).