The first issue here is your rune choices.

Warwick already does good damage with his auto attacks so there's no need to supplement that with flat AD runes. This is doubly true since Hunter's Machete gives you +10AD in every damage calculation against monsters (the jungle creeps). A much better choice for your marks would be 9x Greater Mark of Attack Speed or greater mark of hybrid penetration. The first choice gives you a much stronger early game (due to the majority of your damage coming from auto attacks), and it helps you get better sustain in the jungle than you would with any other marks. The second choice gives you a much better late game since Warwick does a high amount of mixed damage, especially when he has Feral Flare with either a Wit's End or Blade of the Ruined King to supplement his DPS.

Now your seals are good. I think that pretty much everyone except for mid lane should be taking flat armor seals right now. Even after the 4.08 nerfs (I think this was the patch) Greater Seal of Armor still give you the best late game protection since most champions don't build more than one armor item at most. It also helps significantly with tanking physical damage in the early game, this is super important for junglers. Granted Warwick just sustains it back up, but it helps to have 100 extra hp if you get invaded on your second buff.

As for your glyphs, these are okay but I think there are other good options available for Warwick. On 4.14 no one really picks AP based junglers (except for the random Fiddlesticks or Elise) so you can get away with not having MR in your runes. Warwick also includes 2-3 MR items in his build anyways, so the MR runes can kind of be a waste of your early game potential. 9x Greater Glyph of Attack Speed or Greater Glyph of Ability Power both increase your early DPS and sustain by a lot. The choice really depends on whether or not you plan on maxing your Q or W first (AP for Q, attack speed for W) because he sustains from both his auto attacks and his Q proc. His Q also has a 100% AP ratio so 11AP means 11 more damage on hit (and subsequently 8 more hp back to you). You can still run MR/level glyphs if you're against a double AP comp since those are really popular these days.

Now your quintessences, these are kind of like your marks. Warwick already has crazy innate sustain from his Q and his passive, so taking 4.5% lifesteal in your runes is kind of useless. Since you also have no physical damage early on ( Warwick's base AD is really bad) you don't actually get more than 3-4HP back from these every auto attack. As I said above, attack speed runes are always a great option on Warwick. Getting one more auto attack off with a fully charged passive will give you 2x the sustain from an auto attack with lifesteal runes. You can also fill in movement speed or defensive runes here since they can smooth out your early game a bit.

This is where I have the biggest issue with your guide.

Start most games with Hunter's Machete, a Health Potion, and a Vision Ward. This lets you go ward one of the small river brushes or outside of your second buff, establishing early vision control for your team. I can't tell you how valuable this is for your team, but I can say it's worth more than 100g. Additionally, if Warwick gets a semi-okay leash he doesn't need more than one Health Potion. His built in sustain is more than enough to get you through your first clear and gank, and you shouldn't waste money into items you don't need. We've all seen the Warwick jungle who's walking to top lane with full health and 4 potions left. It's just not worth it.
Firstly I want to say how important that Hunter's Machete is on Warwick. He is probably the single best Feral Flare using champion in the game, and not buying it is such a huge waste. Hunter's Machete might be a pretty useless item on Warwick, but for 450g you can upgrade it into a Madred's Razors which gives you more attack speed and another passive granting you sustain. After you get this item you will never run out of HP against jungle monsters, and because of the +50 on hit magic damage, you get a crazy fast clear time so you can spend more time counterjungling or putting down pressure ganks-both of which are Warwick's main objectives in the early game. Basically, if you take the 800g (roughly) that you have on your first back and get Madred's Razors and Boots you're a lot more threatening to the enemy team, and a lot more, well, Warwicky.

Next I want to talk about the order of your other items. The majority of them are pretty good on Warwick in season 4, so I'm glad that you understand more or less how the champion works. In general, you want to go for your Madred's Razors and Boots then move into constructing your major damage item. When its a game where you're going to be focusing hard on ganking, with or without having your ultimate available, then you're going to want to rush your Blade of the Ruined King. This is also a useful rush item when you think you're going to be dueling the enemy jungler/top laner frequently before teams start grouping up, the lifesteal and %HP damage are really good on Warwick in general. For a lot of other games you're going to want to go for full tank after your Madred's Razors and not bother to pick up any other damage items. These are the kind of games where your only goal is to lock down an enemy carry and survive team fights. If you go for 3 damage items (as you do in your guide), you're simply not going to be able to do that. You have to remember that Warwick has sustains and not heals, so he can't survive a 3 person focus if he does something a little too aggressive. That being said, aiming to get Wit's End and then a Spirit Visage is a great way to deal with a double AP composition because it gives you more duraibility the longer you're in the fight. Moreover, you're going to be putting out alot more damage with your Feral Flare and Eternal Thirst than if you went for Blade of the Ruined King.

Since Warwick isn't really an aggressive gank heavy kind of jungler, he's able to delay finishing his upgraded boots until after his second core item (Botrk, Wit's, tanky stuff). I think Ninja Tabi are a great all around buy for him, because it makes it much easier for him to solo baron/dragon, but I want you to remember not to tunnel on one item. If the enemy team has a strong ADC, a strong duelist champion ( Jax, Aatrox, Irelia, etc), or is a full AD team comp, go for Ninja Tabi. A lot of the time you're going to want to pick up Boots of Swiftness so that you don't get kited in teamfights, this actually synergizes really well with your Blood Scent passive, and other times you're going to want Mercury's Treads if the enemy has more hard cc than they have slows. Once you have your boots upgraded you can go into full tank, Frozen Heart, Spirit Visage, Banshee's Veil, Randuin's Omen, and get to where you're really annoying for the enemy team to deal with. I wouldn't recommend going for a Sunfire Aegis unless you're trying to close out the game, simply because it doesn't do all that much for anyone who is looking to dive the enemy back line, and Randuin's Omen gives you much better stats for not a lot more gold.

This is probably the part where I think you need the most help. Right now your jungle path is all jacked up and it's taking a lot of power out of what Warwick is supposed to do for his team.

Start at the buff that's closest to bot lane, then move to wraiths/wolves, and then on to your top side buff. That means if you're on blue side, start red, if you're on red side, start blue. You do this so that you can get a harder leash from your team without putting anyone behind in cs (2-3 players is always going to be stronger than 1-2), and so that you can support your top laner for the lv3 (2:40-3:00) gank from the enemy jungler. Warwick excels at counter jungling and counter ganking because he's so damned hard to kill, so you want to abuse that as much as you can. His one real weakness is that he has no cc before level 6, so if you can have your top bait a fight into you (instead of trying to initiate yourself) then you're going to have a much better chance to force first blood. Ward the river brush/enemy tri brush and attempt to countergank top lane. Because Warwick has these fast clear times, its easy for him to get into position for counter ganks simply because there's very few junglers who can beat him in getting to top lane. You drop the ward so you know when to hit your go button and go ham on the enemy. It's generally easier for you to have your top lane move down and 2v1 the jungler, then turn and 2v1 the enemy top lane. Tell them what you want to do before you get into game, and then a ping should be all the explanation they need to get the job done. Remember, if you manage to burn enemy summoner spells, and no one on your team dies or has to use theirs, the gank is an overall success for your team. You don't have to get kills for a gank to be useful. If you survive the gank and there's no immediate threat to your life, move to clear out your wolves and wraith camps, then head to base and buy. This is pretty self explanatory. Get thee to a nunnery.