Zerg Reconnaissance Tips
Zerg reconnaissance capability is probably the best of the three races.
Terrans have the ComSat, but it gives but a fleeting peek at the enemy
and costs mana. It takes two or even three ComSat stations for Terrans to
have a good reliable recon method that can be used at a moment's notice.
Protoss have the permanently cloaked Observers, but these are useless
for peering inside fortified bases that contain detector units.
Zerg have a variety of means with which to keep tabs on the enemy and
they should all be utilized as much as possible. One overlooked (for its
recon capability) unit is the Zergling. They're cheap and can easily be
scattered around the map. Ideal places to have them are next to possible
expansion points and along heavily traveled routes (such as the areas in
between your base and the enemy's). Simply scatter them anywhere you
suspect your enemy may move through and burrow them. Often times,
your opponent will neglect to keep a detector with their group as they
approach your base, so they won't know they're being watched. If you
have burrowed Zerglings all along the route, all you have to do is keep one
eye on the mini map, and you'll be alerted to their approach. You'll even
see what types of units and how many the enemy is bringing! This
information is literally priceless because it prepares you for their attack. If
you have the strength or inclination, you can launch a pre-emptive strike
on them as they're traveling. Often times this can be annoying to your
opponent because they're not prepared mentally to have a battle when
they're en route to your base.
If you need to keep an eye on different islands in an island game, consider
using Scourges. It's risky to leave Overlords over each island because
they're tempting targets for roaming enemy fighters. Scourges are
relatively cheap and are fast enough to get out of trouble too. Stick a
Scourge over each island.
A more common way Zerg players recon their opponents is to use the
Queen's Parasite ability. This is a great spell and should be used on units
within the enemy base before you attack. This will alert you to the most
fortified areas of the enemy base. Parasites can also alert you to the
location and number of the most dangerous enemy units like Siege Tanks
and Templars. The ability to see the enemy defenses can allow you to
adapt your attack. What some people don't realize is that the most
effective Parasite is one that the opponent doesn't know about. Instead of
waltzing your Queen in and Parasiting an enemy unit out in the open, try
using a distraction attack on your enemy, then Parasite something far
away from the distraction. For example, have a couple Mutas attack the
rear of your opponent's base. While that's happening, bring in a Queen
and Parasite some of the units up front. Chances are, your enemy won't
notice, so you'll get a much better and LONGER view of the enemy base
this way. Scoot your distraction forces out when you're done.