House Sparrow attacks on Purple Martin nests

This page was last updated on: May 4, 2006

Eurasian House Sparrows are a non-native bird species that was introduced to the US in the 1800's.  It is a cavity nester and poses many problems for the martins when it attempts to build it's nest in the compartments of martin houses.  In the eastern US, Purple Martins nest only in man-made structures, so if the sparrow is allowed to takeover a martin house, the martins have nowhere to go.  Active martin landlords do their best to prevent the sparrows from doing this by removing the sparrow nests - this is legal, as House Sparrows are not protected, being a non-native species.  Unfortunately, no matter how carefully an active martin landlord monitors his colony,  the sparrows often get into an occupied compartment, where they will peck holes in the eggs and then build their own nest right over the top of the martin's nest. 

During our 2005 season, we had numerous sparrow attacks on our martin house.  On April 13th, I photographed a male House Sparrow checking out B2, which at that time was unoccupied.  He was seen off by the martins - see the 2 photos below, but usually the martins are not aggressive enough to keep the sparrows out. 
Two male Purple Martins seeing off the intruder on April 13th
Male House Sparrow outside the B2 compartment - April 13th
The sparrows will frequently go into occupied compartments, break the eggs and build over the top of the martin nest.  See the photos below, taken on May 2nd, when we found the devastation in T6.  We had been away for 6 days, so had not been able to monitor this particular attack.  We removed the sparrow nesting material, which is mostly grass, and hoped that our pair of martins would move back in.  Fortunately they did and laid 4 more eggs, which hatched successfully - see the 3rd photo below.
Another view of the broken martin eggs - May 2nd.
Three broken eggs from T6, with the brown leaves that the martins cover their eggs with, plus the sparrow's grass nesting material.
Four martin nestlings from the re-nesting attempt in T6 - June 3rd.
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