On this page of the game guide to Borderlands 2 you will find the walkthrough description of the main mission titled Wildlife Preservation. After beginning the quest in Sanctuary it will be necessary to visit a location named Wildlife Exploitation Preserve.
Wildlife Exploitation Preserve
6) Hyperion headquarters
7) Slag Sample 1, 2
8) Gate/Super Badass Loader
9) Slag Sample 3, 4
10) Bloodwing's cell
11) Slag Sample 5, 6
12) Hyperion warehouse
13) Slag Sample 7, 8
Speak to Roland  and use Fast Travel to get to The Highlands Hyperion Bridge. Follow the passage in the south-east part of the map to reach Wildlife Exploitation Preserve. Cross the stone bridge from the above screenshot  and head up the path to reach Mordecai's hideout .
After you learn about the plan, head to the gate  in the first camp. When you try to open the passage with the button, the door will be blocked and you will have to critically damage three GUN Loaders. Reduce their health to around 20% and the passage will become unlocked.
Head deeper into the preserve, towards the observatory marked with . Head through the room and you will once again reach an open space. Eventually you will reach Hyperion headquarters . Open the door with the button on the left side. Inside one of the rooms you will find two Slag Samples . In return for finding 10 samples you will receive bonus experience points. Samples can also fall out of defeated enemies.
You will reach a locked gate . Keep fighting with all the appearing Robots and Stalkers (including a Badass) until a passage opens and a Super Badass Loader appears. Hide behind covers when it shoots and wait for the gun to overheat. Use the time between them to attack the Robot.
In the room marked as  you will find two more Slag Samples. One can be found after killing the Loot Midget which will jump out of the cardboard box on the right side of the room.
As you reach Bloodwing's cell , it will turn out to be empty. Pick up the Feather and return to the previous room. All the cages will become unlocked which will also let you reach the further locations. Inside room  you will find two more Slag Samples.
As you reach the Hyperion warehouse , the entrance will turn out to be locked. You will need to open a proper amount of Skags for the passage to open. Inside, in room  you will find two more Slag Samples (you should have collected the missing ones from dead enemies).
Go up the stairs onto the bridge leading to a room with an elevator which you have to use to reach Bloodwing . The battle can be divided into three phases. Firstly the bird will surround itself with fire. When it flies onto you, run to the sides and shoot after dodging the attack. The bird can also hang in the air and shoot fireballs at you, but you should be able to easily dodge them.
After losing enough health, it will switch to an electric cover. Skags will also appear on the arena, you can use them for Second Wind. The last form will be acid. The tactic stays the same: dodge the charge and shoot at Bloodwing. When the boss finally falls down to the ground, take the Microchip from its neck. Now quickly head back to a safe distance. Eventually a shortcut will open up on the left side of the arena, leading to gate . Use Fast Travel, return to Sanctuary and head to Claptrap . Install the new chip and return to Roland  to end the mission.