The Crescent Entrance Hole can be found on the SuperGourd and many commercially made metal and plastic houses.   It looks like a half-moon.  It is one of the oldest starling-resistant entrances.  This entrance was developed by the late Charles McEwen.  It works fairly well in wooden houses.  Our experience shows that metal/plastic housing using the Crescent entrance need a wing entrapment guard to "thicken" the entrance making it safer for the martins and eliminating wing entrapment.  


Very effective against European Starlings.

Must be porched both inside and outside of the gourd.  This aids the martin entrance and hinders the starlings.  The newer SuperGourds have drill guides and porches are included with the gourd.

Crescent Hole Plugs are ideal to keep unwanted birds out of your gourds or housing. 


Must be exact dimension or the starling can breech the entrance.

For metal/plastic housing porch must be installed within 1/16" of the bottom of the crescent entrance.  To high or too low the starling can use the leverage to force itself in, or keep the martin out.

Longer learning curve for the martins to learn to navigate (verses the Conley II)

 The Conley II entrance hole is also a Starling-resisitant Entrance Hole.  This entrance was developed by Willie Conley.  He was the first landlord to have a successful colony of over 100 breeding pairs using his entrance.  There is a dip in the bottom/center of the entrance and the sides are 100 thousands of an inch  less than the dip.  This is so the starling can't turn itself to the side to gain entry.  


This entrance is the most popular and the easiest for the martins to learn to navigate. 


Studies have shown that some starlings are slightly smaller than ours in the north.  These smaller starlings can occasionally breech the entrance.  In 2023 the Troyers developed the "Starling Stopper" that works in conjunction with the Troyer Tunnel found on the vertical and horizontal gourd.  

In conclusion, new and seasoned martin landlords start/add housing use exclusively starling-resistant entrance holes.  Please don't be afraid to try them.

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