House Martins – Ray Colliers Wildlife in the North

house martinsSome readers may now be fortunate  to have house martins feeding chicks in nests under the eaves of houses.  However, this year has not been easy for them after their long journey from their wintering quarters in Africa.  This also involved crossing the massive Sahara Desert which is a feat in itself.   When they arrived back the birds faced a shortage of their food, insects.   The  concentrations  of insects  were only to be found on large and small lochs such as those at Dochfour and Loch Flemington.  Large numbers of house martins and their relations, sand martins and swallows, also gathered and they were quite a sight wheeling and dipping over the water.   A few house martins went off to inspect  last years nests but these would have been the older males who , in  any case, were the earliest to have returned from Africa.   Then, when the insects levels rose in  general, the birds were back at their nesting colonies and assessing which nests could manage with refurbishment and which would need a new build completely.    This was important as not any old mud  would do as it had to be the right consistency.    What may look like good mud to us was often just ignored and the birds would go some distance for the right type.  The right mud is very important as the new nest may take up to  two weeks to complete and will take over 1,000 beakfulls of mud.  No mean feat, so it just as well that both the  male and  female assist in the building or refurbishment.  The problems have only just begun as the insect supplies may run  low and in extreme cases it has been  known for the adult to just leave the chicks  in the nests and set off back  south as it is more important they at least live to come back the next year to breed again.   In contrast in summers when the insect levels are  maintained  at a  high level there may be two successful broods with both fledging alright.

Then  comes one of the mysteries  of the bird world that has still not been solved as where do these birds go?  We know that they go to Africa but, like the swallows  and sand martins,   they do not seem to congregate and roost anywhere.   Even before  they leave this country, unlike the swallows and sand martins that gather in huge roosts, the house martins just seem to disappear.   Normally such mysteries can  be solved by extensive ringing of birds but where and how do you catch them?  Looking at the numbers of each birds ringed in the Highlands each year gives an idea of the problem. Each year around 1,000 swallows are ringed and 500 sand martins.  The total each year for house martins is around  10!.  It is very difficult to get results from the 10 house martins ringed.   So with no birds found in Africa from ringing just where do they go there.  One theory  is that they, like swifts, do not land again from the time they leave the nest to the time they go to Africa  and then back again.   So that means that house martins eat and sleep when they are in flight.  This is understandable  as they feed on insects that are flying – but flying and sleeping at the same time?    So when the end of the season comes for the house martins feeding chicks watch for them to finally depart and just wonder what they do before they return  to you the next year.  Mysteries about wildlife is what makes it more intriguing and fascinating.

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