This chapter presents an in-depth study of applying wireless sensor networks (WSNs) to real-world habitat monitoring. The authors developed system design requirements covering hardware, software, enclosures, and architecture to meet the needs of biologists. In 2002, 43 nodes were deployed on a remote island, streaming live data to the web. Despite challenges in real-world deployments, the authors collected environmental and node data to evaluate system performance. The close integration of WSNs with their environment enabled high-density environmental data collection. Sensor data was also useful for predicting system operation and network failures. Based on over a million data readings, the authors analyzed node and network design, developing reliability profiles and failure models. The chapter discusses the need for WSNs in habitat monitoring, the network architecture for data flow, the WSN application, and network behaviors deduced from sensor data. It also covers related work and concludes with the impact of sensor networks on habitat and environmental monitoring. Habitat monitoring requires high-fidelity data, which traditional methods cannot provide. Wireless sensor networks offer a solution by enabling real-time data access without repeated visits to sensitive habitats. They are particularly useful for monitoring microclimates and burrow environments. The authors deployed a 43-node sensor network on Great Duck Island, monitoring Leach's Storm Petrels. The network architecture included sensor nodes, gateways, and a base station. The system was designed to operate for an entire field season with low power consumption. The application software was simplified to minimize development efforts and leverage existing platforms. The sensor board included sensors for light, temperature, humidity, pressure, and infrared radiation. The packaging strategy focused on waterproofing and minimizing interference with the environment. The authors identified several node failures, including issues with humidity sensors and clock skew. They analyzed the network performance, noting packet loss and phase drift. The study highlights the importance of sensor reliability and network longevity in habitat monitoring. The results provide insights into the behavior of wireless sensor networks and their potential for long-term environmental monitoring.This chapter presents an in-depth study of applying wireless sensor networks (WSNs) to real-world habitat monitoring. The authors developed system design requirements covering hardware, software, enclosures, and architecture to meet the needs of biologists. In 2002, 43 nodes were deployed on a remote island, streaming live data to the web. Despite challenges in real-world deployments, the authors collected environmental and node data to evaluate system performance. The close integration of WSNs with their environment enabled high-density environmental data collection. Sensor data was also useful for predicting system operation and network failures. Based on over a million data readings, the authors analyzed node and network design, developing reliability profiles and failure models. The chapter discusses the need for WSNs in habitat monitoring, the network architecture for data flow, the WSN application, and network behaviors deduced from sensor data. It also covers related work and concludes with the impact of sensor networks on habitat and environmental monitoring. Habitat monitoring requires high-fidelity data, which traditional methods cannot provide. Wireless sensor networks offer a solution by enabling real-time data access without repeated visits to sensitive habitats. They are particularly useful for monitoring microclimates and burrow environments. The authors deployed a 43-node sensor network on Great Duck Island, monitoring Leach's Storm Petrels. The network architecture included sensor nodes, gateways, and a base station. The system was designed to operate for an entire field season with low power consumption. The application software was simplified to minimize development efforts and leverage existing platforms. The sensor board included sensors for light, temperature, humidity, pressure, and infrared radiation. The packaging strategy focused on waterproofing and minimizing interference with the environment. The authors identified several node failures, including issues with humidity sensors and clock skew. They analyzed the network performance, noting packet loss and phase drift. The study highlights the importance of sensor reliability and network longevity in habitat monitoring. The results provide insights into the behavior of wireless sensor networks and their potential for long-term environmental monitoring.