|The Ottoman empire lost territory during the Balkan Wars.|
The Balkan wars were a result of the collapsing and retreating Ottoman Empire who had control of the area at the time. The European powers desired the land and to reclaim it from their former Muslim foe. This led to the rise of Serbia and the rivalry between Austria and Russia over influence on the land. Conflicts erupted when Russia encouraged nationalism in Serbia, and Serbia thus wanted to annex parts of Austria. Because of these things, the Balkan Wars ensured mostly as a quick land grab to see who could obtain the land in the area.
The Balkan Wars became a primary concern for Germany and Austria-Hungary mostly because Russia supported Serbia (which was a growing power in the Balkan area). Thus the German Imperial War Council was held. The idea was that in Britain's sole alliance with France, the escalating importance of the Balkan wars, its influence by Russia, and threat to Austria proved that Germany needed to act fast if it wanted world power. Wilhelm greatly stirred up the meeting, as it was a time of "war now or never".
The Treaty of Bucharest is the result of the two wars in which Serbia gained much land from Slav territory in Austria and surrounding areas. The wars increased nationalism in Serbia (which threatened Austria-Hungary directly) and thus provoked Austria to use its armies more. If anything, the Balkan Wars, along with the culmination of the four general causes, is what led to Austria-Hungary blaming Serbia for the assassination of the archduke. The amount of tension led to the blame game which inevitably led to War.