can you name some specific species of that first migratory bird which you mentioned earlier?
Barn Swallow
Barn swallow
The barn swallow ("Hirundo rustica") is the most widespread species of swallow in the world.
when do birds start flying south for the winter It a regular seasonal movement, often north and south, undertaken in response to changes in food availability, habitat, or weather.  The most common pattern involves flying north in the spring to breed in the temperate or Arctic summer and returning in the autumn to wintering grounds in warmer regions to the south. can you name some of these migratory species? Swallows, wildfowl, the pink-footed goose and finch are some of them. how do these species navigate to a certain area? Navigation is based on a variety of senses. Many birds have been shown to use a sun compass. Some also use a combination of skills like, the ability to detect magnetic fields or use visual landmarks as well as olfactory cues. can you give me an example of how the studies were carried out for their migration? Some of the techniques include, marking the specie, radar and satellite tracking. what are the threats these species face during migration? Since their travel involves crossing political boundaries of countries, it can put species at risk if any convservation measure is not put in place. Many spectacular migrants have already gone extinct due to this. can you name a few birds who migrate in the night? UNANSWERABLE earlier you had mentioned some migratory species, in which country/region is the first species commonly found? Europe, Africa and Northern America region. which family do they belong to as per the scientific classification? Passerine birds.
wiki:13389674
Barn swallow [SEP] Introduction
The barn swallow ("Hirundo rustica") is the most widespread species of swallow in the world. It is a distinctive passerine bird with blue upperparts and a long, deeply forked tail. It is found in Europe, Asia, Africa and the Americas. In Anglophone Europe it is just called the swallow; in Northern Europe it is the only common species called a "swallow" rather than a "martin". There are six subspecies of barn swallow, which breed across the Northern Hemisphere. Four are strongly migratory, and their wintering grounds cover much of the Southern Hemisphere as far south as central Argentina, the Cape Province of South Africa, and northern Australia.