At the end of Addison Court, past the four parking spaces and an old outhouse, a short trail climbs through tropical hardwoods and past walls of stacked whelk shells. It's one of the highest points in Collier County, and houses surround it on every side. From September through November, the preserve's eBird checklists fill with warblers, vireos and thrushes.
Otter Mound Preserve covers 2.47 acres at 1831 Addison Court. Conservation Collier, Collier County's land conservation program, manages it. Most Estates neighbors know it as a history stop. Every fall it also works as a refueling stop for migrating birds, and the bird records show it.
October Has the Longest List
The preserve has its own hotspot page on eBird, the bird-sighting database run by the Cornell Lab of Ornithology. Across all years of checklists, birders have recorded 180 species there. Broken out by month, the fall numbers look like this:
| Month, all years combined | Species recorded at Otter Mound |
|---|---|
| September | 97 |
| October | 109 |
| November | 73 |
| All months | 180 |
More than half of every species ever logged on this lot has turned up in October in at least one year. By November the list is about a third shorter than October's. In late October, the end of the busiest stretch is near.
These are cumulative totals. They show what has been recorded over many seasons, not what a single morning walk will find. Conservation Collier makes the same point in its own event listing: "Sightings are not guaranteed," and weather, temperature and wind decide whether migrants arrive on a given day.
The Names on the Fall List
The fall checklists read like the warbler pages of a field guide. The Otter Mound filters for September, October and November all include these species:
- Cape May Warbler
- Black-throated Blue Warbler
- Magnolia Warbler
- Prairie Warbler
- Palm Warbler
- Black-and-white Warbler
- Ovenbird
- Red-eyed Vireo
A few more species show up in the September and October records but not on November's list. They include Swainson's Thrush, Swainson's Warbler and, in September, Yellow-billed Cuckoo. Most of these birds forage in leaves and under shrubs. An Ovenbird walks the leaf litter. A Black-and-white Warbler creeps along bark. A thrush stays low in the undergrowth. None of them would find much to eat on a lawn or a seawall, and that explains why this particular lot gets so much use.
Why Birds Pick This Lot
The 2023–2033 management plan that the Collier County commissioners approved for the preserve classifies it as tropical hardwood hammock. The county is managing it toward a native canopy and understory of gumbo limbo, soapberry, false mastic, stoppers, wild coffee, firebush, rouge plant, scorpion tail and blue porterweed. That mix supplies fruit, flowers, insects and cover in a small area, which is what a tired migrant needs.
Audubon Florida has described the same thing in small patches of habitat on Marco Island. In a spring 2024 Birdathon report, the team's first stop was the gumbo limbo and sea grape strip between the Tigertail Beach parking lot and the sand, and they wrote:
"Fresh off their long, migratory flights, birds find fruit and seeds, glean insects from leaves and bark, forage for insects in the air, and even gorge on nectar and pollen in this sliver of habitat that most people barely notice."
From Tigertail, the same team drove to Otter Mound. They described it as an ancient shell mound of about two acres, covered in tropical hardwoods and surrounded by houses, and they counted 17 species there, including Black-throated Blue Warbler, Cedar Waxwing and Yellow-billed Cuckoo. That count came during spring migration, when birds head north. The fall eBird totals show the southbound flight using the same trees.
Butterflies use the hammock too. The management plan records monarchs, Gulf fritillaries, zebra longwings and eastern tiger swallowtails, but it notes that no formal invertebrate survey has been done. The plan also lists seven state-listed plants on the property: Curacao bush, giant wild pine, Florida thatch palm, satin leaf, red stopper, lignum vitae and barbed-wire cactus.
The Hammock Grew on Shell Built Twice
The trees grow on high ground, and people built that ground twice.
The first builders were Calusa. Otter Mound is part of the Caxambas Point archaeological site, a complex of Calusa shell features covering 70 to 80 acres that people lived on from around 750 to 1200 A.D. The preserve also sits within the footprint of historic Caxambas Village.
The second builder was Ernest Otter. According to the county plan, Jim and Tommie Barfield owned the land and sold it to Charles Griner in 1919. Ernest and Gladys Otter bought it later. Through the 1940s, 1950s and 1960s, Mr. Otter built the terraced walls with ancient whelk shells he found on the property. A house built on the site in 1923 burned in 1978, and the outhouse is the only structure left.
Collier County bought the main parcel in July 2004 and a southern parcel in June 2007, and the preserve opened to the public in March 2007. Because the lot was protected for its archaeology, its hammock survived among the house lots around it. The rare plants and the October warbler counts both followed from that.
Nearby, a historical marker for Indian Hill and the Barfield homesite stands at Scott Drive and Indian Hill. According to Coastal Breeze News, the marker ties the spot to the Heights Hotel, the Barfield family and the former Caxambas School.
The county plan also records recent restoration work. Crews began treating and removing invasive royal poinciana in 2021, planted trees and shrubs in 2022, and cleaned up Hurricane Ian debris and cleared the trail in 2022 and 2023. The understory birds find this fall comes partly from that replanting.
How the Preserve Works on a Weekday Morning
The county's preserve listing gives daily access from dawn to dusk, with parking on site. In practice:
- Parking: Four public spaces at the entrance, including one accessible space. Neighbors within walking distance can leave those spaces for visitors.
- Trail: The original trail ran about 1,000 feet and included a sidewalk section built for wheelchair access. A slow loop with binoculars fits easily before the day warms up.
- Rules: The county's management plan asks visitors to stay on the trail and prohibits unleashed pets, dumping, unauthorized vehicles, and removing or damaging natural, historical or archaeological resources.
- Questions: Conservation Collier takes event questions at [email protected] or 239-252-2961.
Conservation Collier manages the site and shares day-to-day upkeep with the City of Marco Island under an interlocal agreement.
On October 20, Conservation Collier held "Following the Flyway: Fall Migration at Otter Mound Preserve," a three-hour morning walk led by one of its land managers. The program is part of the county's guided hikes series on Eventbrite. Conservation Collier follows the walk timing that "has produced migrant sightings in previous years," so the series is the place to watch for its next walk at the preserve.
Where the Season Goes From Here
As the October totals give way to November's shorter list, the birding moves to winter waterbirds. Audubon Western Everglades has these guided outings on its calendar, each running from 7:30 to 10:30 a.m.:
- November 7, 2026: Marsh Trail, Ten Thousand Islands, south of the Marco turnoff. The outing includes a short walk to watch roosting birds leave at sunrise.
- November 14, 2026: Freedom Park in Naples, a 50-acre wetland with a boardwalk.
- December 5, 2026: Eagle Lakes Park, for winter waterbirds and songbirds.
Some of the warblers on the Otter Mound fall list stay past the migration window. Palm, Prairie, Cape May, Black-throated Blue and Black-and-white Warblers all appear on the November checklists. The hammock on Addison Court is worth walking again after the October peak.
A good part of what makes The Estates special is a shell mound that someone terraced by hand and protected land that birds still use every fall. If you'd like to talk about life on the south end of the island, from Caxambas history to the quiet streets around Indian Hill, Devin Sweazy Group is glad to help. Schedule a Consultation.
