After several years of low tallies, bald eagles made a resurgence in the Fort Riley area during the 2018-2019 season.Compared to numbers observed last season -totaling little more than 50 - bald eagles observed Jan. 30 by wildlife biologist Mike Houck, environmental division, Directorate of Public Works, increased more than six-fold, topping 300.Houck noted the Fort Riley area, specifically the confluence of the Republican and Smokey Hill Rivers giving neighboring Junction City its name, provide ideal conditions for the eagles migrating south as the weather turns colder up north."I think they stay here because they like the big mature trees, the cottonwood and sycamore trees we have down by the river," Houck said. Additionally, the rivers provide access to open water, as opposed to lakes which tend to freeze over."When the river is running, and there's fish in the water, it's a perfect environment for those birds to congregate," he said.If the location consistently provides the right conditions, what's so different this year as compared to recent seasons that saw fewer eagles? Houck says milder winters were likely to blame."As long as there's open water and there's food available, those eagles are going to stay up north," Houck said. "But once everything freezes up, it gets harder. So all the birds get pushed down south to places like Kansas."As opportunistic eaters, Houck said if there's still a good food source near their northern homes, the eagles are likely to stay put.But not all eagles necessarily choose to migrate with the seasons.In addition to the wave of seasonal visitors that congregate at the winter communal roosts each January, Fort Riley is home to a number of resident bald eagles that make it their home year around."In the area we have anywhere from five to nine active nests that I can think of," Houck said. "On Fort Riley, we have the Madison Creek birds, up north in the training area, that have been there since 2004."Fortunately, the Madison Creek pair puts up with the influx of visitors fairly well."Normally, they're territorial enough that they'll run all the other birds off," Houck said. "But, this being a gathering area, this roost site, they seem fairly tolerant of the other birds, for now."Houck said Bald Eagles in the wild can live 15 to 20 years, which means the Madison Creek pair might be nearing the end of their lifespan."They've been out there for 15 years already, so I keep thinking one of these years, we might lose them," he said. "They mate for life. But if you lose one, they'll take another mate and then they might move somewhere else. It's usually the male that picks the nesting location, so if you lose the male, the female might move someplace totally different with a new mate."Houck said they can tell the Madison Creek pair are the same pair year after year because of the colored band the male has on his leg. The characteristics of the band tell Fort Riley's wildlife biologists the eagle originally came from the Clinton Reservoir, the same site as the original first pair of eagles that started re-nesting in Kansas in 1989 after populations began to recover.After nearly disappearing from most of the United States decades ago, bald eagles are once again thriving and were officially removed from the federal list of threatened and endangered species in 2007, according to the U.S. Fish and Wildlife website.The website notes that the two main factors that led to the recovery of the bald eagle were the banning of the pesticide DDT and habitat protection afforded by the Endangered Species Act for nesting sites and important feeding and roost sites.Even though they are no longer endangered, because their range is expanding throughout the United States, Houck says just about every military installation has some management program."When they were listed as threatened and endangered, we integrated them into our natural resource management plan - we had management plans for the eagles," he said. "And we still have some today. Because, even though they're not protected by the Endangered Species Act, they are still protected under the Bald and Golden Eagle Protection Act."So eagles continue to be counted and monitored, and Fort Riley's wildlife biologists incorporate their own banding program into their management plan, which they do every spring as new eagles hatch on post. Fort Riley also tries to protect their eagles from possible disturbances by doing things like notifying the airfield of their locations so that helicopters can try to avoid the nesting sites.Houck said although bald eagles are fortunate to have one of the more successful comeback stories, conservation efforts are still important."Everything has a fit," he said. "All the predators are important. They all have their place in the environment."