The bird-lover has been offering free Sunday morning tours of the 1800-acre park for 21 years. His next tours are scheduled for August 14 and September 11, at 8:15 a.m.
"We have a pretty faithful crew in the spring and the fall," said avian enthusiast Leslie Roche, who attended the July 10 tour.
Mardones led the group from the park's visitor center through the sloped field where the Battle of Monmouth was once fought, and along the way, he and Roche scoped out birds in the grass, trees, and skies with binoculars and a telescope.
Some species spotted include: a Common Flicker, American Robin, Yellow Warbler, Great Crested Flycatcher, Catbird, and a Red-tailed Hawk.
July proved to be a difficult time for bird watching because full foliage makes it tough to spot in trees, and the end of the mating season means males no longer perform ostentatious displays. Fortunately, bird watching is about listening too.
"Finding them can be done either visually or audially, each bird has a distinct call," Mardones said, who recognized the songs of a Cuckoo and a Mockingbird hidden in the forest.
"But this time of year there's a lot of young birds who haven't mastered the songs they're supposed to sing yet, so when trying to identify a bird by ear it takes a minute to realize you're hearing an incomplete song."
Later, Mardones walked around the park's picnic table area to check in on the nesting boxes that the Battlefield had constructed for Bluebirds, which are threatened locally by invasive species.
Bluebirds make their nests in cavities to protect their young, but they face competition for prime nesting sites from aggressive Starlings, which were accidentally introduced to North America from Europe.
The small wooden boxes on a pole provide a safe place for Bluebirds to make a home if they choose to spend their summers here, and many do. Mardones and other volunteers make sure Starlings or bees don't take over the boxes. They ensure Bluebird nests are free of parasites.
When Mardones surveys the nesting boxes every month, he keeps a record of how many nests, eggs, and babies are present. Since April of this year, he has counted 34 successful bluebird fledglings that grew up in the park's boxes.
The tour also stopped at the stream in the valley separating the park from Battleground Orchards, where Mardones first observed a new beaver dam in January of this year. He hypothesized the beavers relocated to this site because of a construction project futher upstream where a lodge used to be.
"They choose sites based on available vegetation, good water, and little human disturbance," Mardones said. "Aside from people like us and the occasional park visitor with a dog, there's very few people around."
The beaver dam has transformed a section of the stream into a stagnant pond and raised the water level about two feet, so it is almost at the level of the foot bridges, which has reenactors concerned they might be wading onto the battlefield next summer. The flooding drowned some plants on what used to be the stream's banks, but new ones better adapted to the still water have taken root. Today, brand new park residents were discovered in the beavers' pond: two inch long fish fry.
"It's so great to see them! Fish are great at controlling mosquitos," said an enthusiastic Roche. "I wonder if they were seeded by the park or they got here naturally?"
How would fish get from still pond to still pond naturally? One method, ironically, is by way of seafood-hungry birds that splash around in search of fish or frogs to eat. As they hunt, fish eggs in the water can adhere to their legs, and then fall off and hatch many miles away in the next pond they land in.
Nano Mardones leads informative and insightful bird walks of Monmouth Battlefield State Park every month. See the schedule here. You can spot him next on Sunday, August 14 at 8:30 a.m. in front of the vistor center. Bring binoculars, bug spray, and a passion for nature.