The United Kingdom has had a longstanding milk distribution system. Milkmen in small trucks bring the milk in bottles to each country house. Early in the 20th century, these bottles had no top, giving birds easy access to the cream on top.

The titmice and the robins capitalized most on this opportunity, quickly learning to siphon off the cream from the bottles.

In the 1940s dairies began to install aluminum seals on milk bottles, effectively preventing the birds from gaining access.

This worked for a while but one by one, the titmice learned to pierce the tops and before long, the entire titmouse population was only mildly inconvenienced by the aluminum caps.

Other than an occasional few, the robins as a species never learned how to get around the bottle cap and were foiled (no pun intended) from getting at the milky cream.

Why? After all, robins and titmice are similar in size and physical characteristics. The difference was in how the birds interacted within their own species.

Robins are individualistic, self-serving and territorial birds. Rather than cooperate, they chase each other off when approached.

Titmice, on the other hand, are communal birds, relying heavily on other titmice for survival. Through this mutual dependency, they cooperate and collaborate, quickly learning from each other and adapting accordingly.

In short, the titmice won the battle against the aluminum caps because they learned from one another, while the self-serving robins, unwilling to share information, found themselves denied access to the sweet cream.

The lesson here is simple: Birds that flock, like titmice, learn faster, evolve more quickly, and increase their chances of survival. This is true for you as well. When you interact with others, you learn – new information, new techniques, and new ways of helping others succeed.

So, in short, build a network of titmice, not robins.

In addition to the types of people in your network, you need to consider the extent to which you know people in your network.

In Getting A Job, author and sociologist Mark Granovetter found that 56% of people found jobs through personal contacts. Not surprising. After all, it is not what you know, but who you know.”

The surprise was that the personal contacts used to obtain these jobs were not family or friends – “close ties”. Rather, most could be classified as “weak ties”. 55.6% reported that they saw their “job-producing” contact only occasionally and 27.8% saw their contact only rarely.

So, when it comes to job hunting – or finding clients – weak ties tend to be more important than strong ties.

Why? Because close ties tend to occupy the same world as you do. A spouse or close friend may share many of the same network contacts as you and is likely to only refer or connect you to people you already know.

Mere acquaintances, or “weak ties”, on the other hand, are much more likely to know people that you do not. While you might share a small overlap in networks, most of the people they know are completely unknown to you.

The take-away? Do NOT rely solely on close ties to fortify your network. A better means is to associate with people you don’t know well – the person from work that you know casually from meetings or trips on the elevator; the person you see every week at church but, beyond a name, you know little else about.

From a networking perspective, the most valuable people aren’t those closest to you. In fact, the more people you know who aren’t close to you, the stronger your position becomes.

In summary, the quality of your relationships matters and one measure of quality is the strength or weakness of the tie. Having lunch with your long-time best buddy can be fun but does little to build your network. If you want to build your network, have lunch with someone you know … but not that well.