Harford Bird Club explains bird irruptions

Birdwatching, twitching, chasing or birding… no matter what you call it, the birdwatching industry has hit an all time high. According to US Fish and Wildlife, $41 million dollars are spent annually by birdwatchers in the United States on trips and equipment. An additional $14.9 million is poured back into the local economy on food lodging and transportation in various birdy locations. The birding hobby has created 666,000 jobs in the industry.

Snowy Owl


When big things happen in the birding world, the local economy benefits. The most recent birding boom in Harford County has been in Havre de Grace.  The Snowy Owl, an artic migrant, that only appears in Harford County approximately every four years is the most recent draw of birders to our beautiful county.

An irruption is defined as a dramatic, irregular migration of large numbers of birds to areas where they aren’t typically found, possibly at a great distance from their normal ranges. A population shift of this magnitude could be attributed to a variety of factors.  Most of the time it is due to a shortage of food in the natural wintering grounds. For example, if the crop of seed producing vegetation was poor, there are no

t enough seeds available for all of the seed-eating birds. In this case, they move south until they find copious amounts of seeds. Raptors such as owls and hawks do not eat seeds, but their food source is dependent upon seeds.  If there are no seeds, the population of rodents and small mammals decreases causing the raptors to fly to a location where seeds are plentiful and rodents are fat and happy.

When food is scarce, the population decreases; when food is plentiful, the population increases.  In the case of raptors, who always irrupt individually and not as a flock, it is often the immature birds and females that are found outside of their area. This makes sense.  The adult males have an established territory and are better at protecting that territory. Females and juveniles are forced to move in order to survive.

Irruption years are exciting, the obvious show stealer is the Snowy Owl, but many other birds can irrupt in Maryland. You may find Red-breasted Nuthatches, White-winged Crossbills, Rough-legged Hawks, Pine and Evening Grosbeaks and more.

Irruption years have heartbreaking undertones for the birds themselves. We turn them into temporary rock stars and talk excitedly about them on email and social media, but these birds are undergoing a change in their normal routine.  Are they stressed? Possibly. Or maybe they have overcome that time period and are just hanging out where they know food is readily available.

The Harford Bird Club is a great resource for those of you wishing to get more information and learn your local birds. The club offers field trips with local birding gurus almost every weekend. Every other month a newsletter is produced sharing the highlights of the previous trips and other birdy news. Months that don’t see a newsletter include a club meeting.  The meetings offer social interaction with other self proclaimed ‘bird nerds’, snacks or dinners and a guest speaker to educate and inspire your birdy habits. You do not need to be a member to attend a meeting. Come check us out and see what you think. We’d love to have you!

Here’s to your luck and the prospect of seeing the bird of your dreams in your backyard!  We look forward to working with the Harford Land Trust on future projects that benefit birds and birdwatching in Harford County!

Amanda Koss

Vice President

Harford Bird Club

Photo by Joe Subelofsky