Case Study: Nesting Gull Colony Management Plan in Milwaukee County

Milwaukee, Wisconsin 2015-2021

Beginning of MBM and Gull Egg Depredation

Migratory Bird Management (MBM) began gull egg depredation in 2008 with nine accounts in Milwaukee County. Seven of these accounts were home to Herring gulls and the other two were massive Ring-billed colonies. It was a humble beginning to gull egg depredation that took several years to gain significant traction.

The Problem

“From 1976 to 2009, populations of ring-bills increased 92%, according to Birds of North America Online. The greatest increases occurred around Lake Michigan. In the nearly 20 years between 1990 and 2009, North American populations of the ring-billed gull grew 250% to an estimated 7.5 million to 10 million.” (Joe Taschler, Milwaukee Journal Sentinel. July 21, 2013.)

Rooftops would become so congested with feces, feathers and dead birds that air ducts, air return filters and drains were all clogged. Much of the feces, debris and juvenile gulls also made its way down to the ground, putting people and birds in harms way. People would be attacked by overly aggressive adult gulls protecting their young while these young ran a high risk of being run over by vehicles. Conditions could be so bad that maintenance staff could not access many components on the rooftops, requiring pressure washing multiple times a week. HVAC technicians and window washers also struggle to get work done with the constant barrage of angry gulls swooping their heads.

Gull Egg Depredation in 2015

In 2015, Migratory Bird Management saw its first significant growth in gull egg depredation accounts. MBM was hired for egg depredation at approximately 35 accounts in the Milwaukee area. MBM acquired the federal permit needed to remove eggs for the customer and submits the gull egg depredation permit report after the season has concluded. Migratory Bird Management then successfully removed over 12,000 Ring-billed eggs and 1,200 Herring gull eggs. As a result, there were no juveniles running around and both the Ring-billed colonies and Herring gulls proceeded to leave by mid-July, as opposed to mid-August as the juveniles grew up.

Figure 1 – The map above shows the approximate locations of the 30+ accounts MBM managed nests at in 2015 throughout Milwaukee County.

Figure 2 – The map shows the approximate locations of the accounts MBM managed nests at in 2015 in the downtown Milwaukee area.

Gull Egg Depredation in 2020

By 2020, Migratory Bird Management was servicing over 90 accounts in Milwaukee County. Through marketing, word of mouth and a tremendous success rate, MBM’s gull egg depredation tripled its amount of work throughout the nesting season in a span of five years, as well as expanding as far north as Sheboygan and as far south as Kenosha.

Figure 3 – The map above shows the approximate locations of the 90 accounts MBM managed nests at in 2020 throughout Milwaukee County.

Figure 4 – The map shows the approximate locations of the accounts MBM managed nests at in 2020 throughout the downtown Milwaukee area.

Gull Nesting Trends

For five years, Migratory Bird Management continued to grow as sites tripled over that period. Even at that rate of growth, egg and nest counts overall declined, especially Ring-billed colonies. Herring Gulls did increase for three years and then drastically dropped off as nesting management became highly successful.

Figure 5 – The graph depicts the success rate MBM has had since 2015. Even as accounts increased, egg and nest counts steadily declined.

“What unbelievable difference compared to the last few years! Three weeks into the ‘season’ we noticed a huge decline in the bird numbers. Four weeks after that the seagulls were almost non-existent. We were never ‘divebombed’ this year. We didn’t have one customer that complained to us about the birds. I didn’t hear one complaint from our employees about the droppings in our parking lot. Nor did they have to go home and wash their cars everyday like the last few years. We never thought seagulls could have such an impact on our business. Thank you again for solving this issue for us. Definitely money well spent!”

Local Business Owner

Long Term Plan

Migratory Bird Management will continue to expand its range of work well outside of Milwaukee, as several accounts throughout Wisconsin have signed up for gull egg depredation. MBM is scheduled to work at over 100 accounts in 2021.