31. This was an historic migration route for Khas people eastward in the late Middle Ages. 32. When hydro power plants were built the salmon spawning grounds and migration routes were destroyed. 33. The migration route is across the Torres Strait, travelling individually or in small groups. 34. Resident orcas leave the coast each fall; their migration routes are still relatively unknown. 35. This may be due to migration routes . 36. Monitoring programs count the number of monarchs in roosts that develop along the migration route . 37. Sailing against these natural migration routes would have been difficult in any ancient style boat. 38. It takes a pretty big storm to open migration routes to and from the spawning grounds. 39. They also were released along traditional migration routes of elk and deer, their natural prey. 40. Reasons may vary from the El Nino weather phenomenon to dry conditions along the migration route .
