The Duchesses and other Animals Stranger mission is far from being one of the shortest optional missions to complete, as you must recover several hard to find items to finish it.
The Duchesses and other Animals Stranger mission is available in Chapter 4 right after completing The Gilded Cage mission. To begin the mission, you must talk with Algernon Wasp in his Growing House, which can be found to the north of Saint Denis. Algernon is looking for some very exotic items and asks Arthur for help.
To complete the first request, you will have to gather 5 Little Egret Plumes, 5 Reddish Egret Plumes, 5 Snowy Egret Plumes, and 15 Lady of the Night Orchids.
To gather the Egret Plumes, you must first kill Egrets and skin them to obtain their feathers. All types of Egrets can be found in the Bayou Nwa area, but the best hunting spot can be found to the west side of the Bayou, a little to the south of the "O" in Lemoyne on the map.
Here, plenty of egrets can be found during the morning hours sitting around in the water: activate Dead Eye and shoot them down as quickly as possible. Once all of the egrets have been killed, skin them to obtain the feathers then ride to Rhodes and back to make them appear again. If you don't want to ride from one point to another, you can also make camp and sleep for a couple of days. It will still take time to get all of the required plumes, but it's much better than wandering around the bayou in search of egrets.
Getting the Lady of the Night Orchids is a little more complicated than getting all of the required Egret Plumes, as you must find them in specific areas. They are found the southern shore of Bayou Nwa, to the north of the Kamassa River and in the northern part of Caliga Hall area. These orchids grow on trees, so make sure to check the ones in these areas with Eagle Eye active to spot them easily.
Once you have all of the required items, head back to Saint Denis and speak to Algernon. He will give you $110 as a reward and another list of items to find.
To complete the second request, you must find 20 Heron Plumes, 7 Lady Slipper Orchid, and 10 Moccasin Orchid.
The 20 Heron Plumes are obtained by killing and then skinning herons. These birds can be found all over the Bayou Nwa area, but the best hunting spot is the same one featuring egrets, on the west side of the bayou. Unlike egrets, however, herons tend to spawn more often past midday. Once you have killed all those found in the area at any given time, ride to Rhodes or sleep for a few days at camp to make them appear again.
The Lady Slipper Orchids are found in the Big Valley area. They grow on trees and may be difficult to spot, so activate Eagle Eye while in the area to spot them easily.
The Moccasin Flower Orchids are found in the Roanoke Ridge area. Like other orchids they grow on trees and Eagle Eye makes it easier to spot them.
Once you have gathered all of the items requested by Algernon, head back to Saint Denis and talk with him to receive $125 as the reward for your trouble, and yet another list of items to find.
For the third request, you must gather 25 Gator Eggs, 3 Acuna’s Star Orchids, 7 Cigar Orchids, and 5 Ghost Orchids.
Gathering 25 Gator Eggs is extremely easy. There are gator nests in all of Bayou Nwa and they can usually be found near grown alligators. If you don't want to risk alerting an alligator for no reason, get as close as possible and activate Eagle Eye: if any nest is nearby, they will be marked by yellow particles. As each nest includes around 5 eggs each, it doesn't take too long to find 25 of them.
The Acuna’s Star Orchids, Cigar Orchids, and Ghost Orchids are all found in the swamps in Bayou Nwa. They grow on trees like other orchids, and using Eagle Eye makes spotting them easier.
Once you have gathered all items, return to Algernon in Saint Denis to receive $150 and yet another list of items to find.
To complete the fourth request from Algernon, you must find 30 Spoonbill Plumes, 10 Rat Tail Orchid, 5 Spider Orchid, and 5 Night Scented Orchid.
The Spoonbill Plumes are obtained by killing and skinning Spoonbills. While they can be found all over the Bayou Nwa area, the best hunting spot is located right next to the "O" in Lemoyne on the map, by the train track. Head to the area, kill all of the birds with the help of Dead Eye, skin them and then either ride to any town or city or sleep at camp to make them appear again. Spoonbills usually spawn at noon.
The Rat Tail Orchids and Spider Orchids can be found in Bayou Nwa, while the Night Scented Orchids are found to the south of Braithwaite Manor. Like for other orchids, use Eagle Eye to spot them on trees.
Once you have found all of the items, get back to Algernon to receive $175 and the fifth and final list of items.
For the final request, you must obtain 5 Clam Shell Orchid, 5 Queen's Orchid, 10 Sparrow Egg Orchid, and 5 Dragon's Mouth Orchid.
These four types of orchid can be found in different regions. Clam Shell Orchids are located to the east of Caliga Hall, Queen's Orchids in near the shores of Lagras, Sparrow Egg Orchids to the north of Roanoke Ridge and Dragon's Mouth Orchids in the Grizzlies East. Using Eagle Eye makes all orchids easier to spot on trees.
Once you have found all of the orchids, return to Saint Denis and speak with Algernon for the last time. You will receive $200, the Exotic Hat and Algernon's Revolver as reward. The mission will also be complete.