Dall Sheep

sheep1Dall Sheep (Ovis dalli dalli) are found throughout the guide use area year round. Their habitat consists of alpine and subalpine. They will be found at different elevations throughout the year. On the north side of the Brooks they are generally found on alpine ridges and outcroppings. They will be on lookout points where they will have a good view of their country. They favor areas where they have good escape from predators in steep rock outcroppings and rugged terrain. Their diet varies throughout the season from dry, frozen grass and lichen on windblown slopes in winter to summer months of a wide variety of vegetation. In summer they seem to prefer mountain slopes and “Salad Bowls”, upper bowls out of the valley that are full of varieties of grasses, sedges, moss, lichen, and dwarf willow. They have four chambers in their stomachs and will feed often times in the evening and go to bed chewing their cud. They will often feed early in the day and bed again late morning to noon. Often times rams will stand and feed throughout the day for short periods, taking turns while other rams in the group nap. Throughout the area I know of several natural mineral licks the sheep will frequent. They will eat dirt and lick rocks in these areas.

In the spring, Ewes of at least three years old will have one lamb. The ewes and lambs will stay in safety of the rocks until the lambs get strong enough to travel. In July and August the lambs and ewes will form large nursery herds. They will be located in areas with abundant feed at lower elevations. Rams are found in bachelor groups, small bands of rams separated out from lambs and ewes. I have seen rams in large nursery herds of sheep before but this is uncommon. One of the largest Dall rams ever harvested in Canada was with a nursery heard of lambs and ewes. However, Rams are generally in groups of all rams ranging in size from 2 to 8. Solo rams are usually Sickle Horns on look outs or old rams that travel alone. I have guided on two old rams (one 13 years old and the other 15 years old) both had been badly injured and were crossing solo low in the valley. Both rams were in poor health and had been living with broken hips for some time. I don’t believe they would have made it through another winter. I have seen large rams traveling solo on other occasions.

The rams will gather with the ewes in October. They will reestablish their social structure with the largest ram holding hierarchy throughout the rut. In winter the sheep will spread out over windblown ridges and slopes to survive the winter months.

I believe rams in their prime, at 8 years of age, are the best breeding stock for ewes. They have the enthusiasm to breed large quantities of ewes in a short time period. This puts the lambs on the ground, being birthed, in a close duration of time in late spring. Having the lambs hit the ground around the same time allows for a higher survival rate from predators. When the breeding is done by older rams well past their prime, they tend to be less aggressive in breeding the ewes. Ewes and ewe’s cycles can be missed consequently causing low lamb to ewe ratios and spreading time frames out that the lambs will hit the ground. By harvesting older rams it allows for a ram in his sexual prime to assume the breeding thus breeding a high population of ewes in a short time period. This also helps scramble the genetics which is important because sheep are very loyal to their home range. Predators like wolves, bears and eagles naturally do this and play a crucial part of the ecosystem. As responsible hunters we need to mimic these practices to have a sustainable resource.

The sheep horns grow throughout the summer and fall months and slow in winter leaving annuli ring that can be counted to age the ram. The rams will often live to 10 years of age and ewes to 14 years of age. Each gender grows horns but the rams out grow the ewes at approximately 3 years of age. At this age rams put extra nutrients into horn growth and ewes will start conceiving. On years of stress from weather and predators or poor health the rams will put on little horn growth. These years the annuli can be easily skipped when aging. You can distinguish these years by scraping your fingernail on the ring and there will be a ring of calcium deposits that is white. In the Arctic, rams carry a wide range of genetics with horn growth. A lot of times I can pick what ranges different rams were shot out of by the characteristics of their horns. In the Brooks we have a few different ram configurations. These configurations are more easily observed in mature rams. The average mature ram have a semetrical full curl that comes back up to the base of the horn. The Arctic Rams are known for being light on mass (12”-13”) compared to other ranges. Their horns will often time flare at the tips when not broomed and be 36” in length. Color in horns can vary from light brown, grey to a deep dark brown. I have seen a few rams that the horns come in tight on the chin and flare out like an Argali ram. These rams usually have horns well over 40” in length. I have filmed rams that I estimate to be between 42” and 46” in length. The rams produced in ANWR make this a trophy area for sport hunters.

full_curlMature rams in August are generally found above 5,000 feet in elevation in upper side drainages out of the main valley and are close to salad bowls for feeding. I believe some of the largest rams will head to the south side of the Brooks Range early in the year for good feed on the drier side of the range. On the south side of the range there are lower populations of sheep but a much higher ram to ewe ratio. I have hunted valleys, just barely, on the south side of the divide that are historically ram holes. I have never seen ewes or signs of ewes with lambs in these areas. I believe these rams often times travel back to the north side to join with ewes after the first fall snow. I have observed and followed on different occasions these rams traveling in snow over to the north side. Each time the rams traveled in a line on a mission, non-stop, to areas on the north side that held high populations of ewes.

The Brooks Range in size and remoteness allows for great sheep habitat and allows for most rams to live to old age and die from natural predators. When we see large declines in populations these declines are usually due to a warm front in early spring. This layer of wet snow refreezes into a thick layer of ice preventing sheep from accessing feed. They will try to travel to find food and get caught in drifted snow or by predators for they have left the safety of their home-range and are now also weak from traveling in tough conditions. This can cause a large population loss and I believe is a natural cycle. If this was to happen we would be forced to limit and possibly cancel hunts to let the population bounce back. Right now our population is and has been strong and steady. The Brooks Range out of most sheep ranges generally has the most stable weather patterns. The Arctic Ocean and Beaufort Sea are covered with ice that sets the Brooks up for dependable climate in the winter months and we don’t have the fluctuation of warm temperatures in winter and early spring like in other sheep ranges.

In the past couple winters in the western Brooks along the Delong Mountains and Central Brooks the sheep population was hit very hard. I found hundreds of dead sheep and saw very few live ones. I could not pinpoint the cause of the crash but the population was hit hard. I don’t believe the population of sheep was effected by the crash east of the Ivashak. I believe this crash was possibly due to the above described weather phenomenon.

 

Population

7In my observations and journals the Arctic sheep populations are strong. I have observed an average of 40 lambs to a 100 ewes between Guilbeau Pass and the Marsh Fork in 2006 and 2007 and again in 2013. These numbers show good populations of sheep in August and September. I would imagine a little better than half of the lamb numbers will make it through winter. This puts the survival rate at approximately 25 yearlings per 100 ewes going into the next fall. At these numbers the sheep populations are very sustainable. The ram population seems to be strong and my estimation is a ratio of 40 rams per 100 ewes based on personal observations in 2007, 2008 and 2013. I found 7 rams in one season that had died from old age or natural causes in 2001. These rams were not harvested by sport hunters and lived a full life. All of the rams were at least 10 years of age. The 10 year old and older rams are the rams we target to harvest. If we can continue to harvest 10 year old rams we will have little effect on the refuge resource.

Dall sheep are found in the Kenai Mountains, the Tok area, the Chugach Mountains, Mentasta, Nutzotin, and northern Wrangell Mountains, and the Delta Controlled Use Area; also on the north side of the Alaska Range east of the Nenana River, west of the Delta River, and south of the Tanana River; in Tanana Hills, in the White Mountains area, and in the Central and Eastern Brooks Range. Watchful and difficult to approach, Dall sheep challenge the hunters and predators who pursue them. The sheep too are challenged by the harsh alpine environments of Alaska and northwestern Canada.

 

Dall Sheep range map

Overall Sheep populations are stable. The Marsh Fork has appr.1200 sq. miles of perfect sheep habitat allowing ten permits for non-residents to come to the refuge and hunt for a trophy ram.

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