Ask BirdGoober: Irruptions, House Maintenance

Andrea and Terry Grabill aka BirdGoober

​Andrea and Terry Grabill answer the latest avian queries


Winter irruptions – what are they?
From Rachel J.

Wild bird populations sometimes get very exciting in winter.  Birds that we’ve not seen in Lower Michigan suddenly appear in great numbers, causing all kinds of talk among birders and feeder watchers. An irruption, or sudden change in the density and distribution of birds can occur for several reasons, but the result is a regional buzz among the birding community as pine siskins, redpolls, red-breasted nuthatches and evening gosbeaks show up in yards where they haven’t been seen for years, even decades.  
 
Irruptions among songbirds are linked to poor seed crops in their northern winter ranges.  With a mild spring and summer, pines produce a low amount of seeds and when fall approaches, these birds are left with little option but to move south, and in large numbers!  This year, pine siskins have arrived and, for the first time that I remember since the 1970s, evening grosbeaks are turning up throughout Southern Michigan!  
 
Owl irruptions bring northern owls south, including great grey, northern saw-whet, northern hawk, and, of course, snowy owls.  Not much brings people out owl watching like a report of snowy owls from the north.  The winter of 2013-14 was called a mega irruption and snowy owls were found as far south as Florida. 
 
Owl irruptions are a factor of the breeding adults being overly successful at raising young.  Every year, parents produce more young than can be supported by the northern food supply of rodents.  In years of high rodent density, these chicks survive at a higher rate and once winter sets in, these rodents become difficult to find.  Often, the surplus owls raised that year are forced to move south in search of prey.  
 
Be on the lookout for irruptions!  Evening grosbeaks and pine siskins are popping up and it’s only a matter of time before some snowy owls are around!
TWG

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Above: Evening grosbeak male and group at a feeder.  Photos by LouAnn McLaren

What steps should be taken for Fall bird house maintenance?
From Heidi B.
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Now that nesting season is over, it is a great time of year to inspect nesting structures.  If there are any rotten materials, now is an opportune time to replace and repair them. The following are some tips for cleaning and winterizing nest boxes:

• Remove all old material and dispose of it away from the nest box, so as not to attract predators.
• Use a stiff-bristled brush to scrape the inside of the box to rid it of any left-over parasites and clean any of the plugged or clogged holes
• If you wish, you can mix a bottle with a cup of vinegar mixed with water (usually one cup to one gallon).  Using a spritz bottle, spray the inside of the nest box down to assure it is parasite free and ready for winter.

 Some people choose to leave the nest boxes up through the winter for small creatures to have some shelter from the elements, while others prefer to remove the nest boxes and then bring them back out in the spring.  Bear in mind that if you choose to leave them out over the winter, you will want to go through the cleaning process once again in the spring before nesting season begins yet again.  The choice is up to you!
 Just remember some fun facts:

• Most owl nest boxes should be repaired and ready in January as these birds nest early.
• American Kestrel, as well as Eastern bluebird boxes should be ready by mid February.
• Wood duck boxes as well as songbird boxes should be cleaned and ready to go by the first week in March.

 Remember, it is all for the love of birds! 
AFG
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BirdGoober is Terry and Andrea Grabill, of Newaygo.  They have been birding together since they met and love to share their passion for birds with people of all ages.  Please send your birding questions to the Grabills at [email protected] or visit their website www.birdgoober.com.