I have an update on my comments. NE has replied and say 'In all cases, in England and the IoM, when one of Natural England’s satellite tagged Hen Harriers stops transmitting the Police are notified straight away and a thorough search of the area is made' That is very interesting but opens up new questions about what the police have done, I also wrote to them but if it ongoing i doubt i will get a reply. In other words another black hole of infornation Strange that the NE Hen Harrier satellite tagged data-sheet mentinons nothing suspicious about birds failing. Why? They write 'Missing Fate Unknown includes: (i) radio-tagged birds that left the study area. The vast majority of Missing Fate Unknown's are radio-tagged birds, this is not surprising given the mobility of Hen Harriers and our relatively small study area. (ii) radio-tagged and satellite tagged birds that were recorded after the battery ran out or transmissions had stopped. (iii) satellite tagged bird that died in such a position as to render the transmitter hard to locate and recover. The satellite transmitters depend on light to recharge, and operate on a 10hr on 48 hr off duty cycle. Therefore, when a bird dies there is only a small chance that it would happen whilst the transmitter is transmitting with enough charge to enable transmission of coordinates and a signal to enable retrieval. If the bird dies in the off cycle of the transmitter then it could have travelled many kms to its final resting place from the last transmitted coordinates. If this final resting place is in long vegetation, and/or the bird is lying on its back with little or no light available the solar panel it will never transmit again and the bird would fall into the Missing Fate Unknown category. '