The presence of learning in organizations is important for success and survival. Recent research into open source software developers has primarily suggested a social constructivist view where knowledge is constructed in the social relationships within the team culture. I report results from a case study that investigated the presence of situated learning among open source developers at an earlier time of a project. Thirty-eight developers were systematically selected and examined on their performance, experience and roles during ten months of maintenance work. I followed a model of learning curve effects that associated the improvement in the average resolving time with the accumulated experience. I found a strong relationship between the two variables and confirmed the presence of learning. In addition, I found a less convincing evidence to affirm knowledge depreciated among open source software developers. The depreciation factor was estimated to be 94 percent, compared to other studies which ranged between 65 to 85 percent. An additional investigation was conducted around the organization structure to understand whether core and peripheral members have different average resolving time. The finding was inconclusive to claim both groups have different means towards issue resolution. The consistency in the result of this thesis and several other related research efforts suggests that learning is likely to be an intrinsic characteristic of open source software development rather than just a speculation in the literatures.