A New Turkey Vulture Migration Route?

For some time now, I have suspected that the numbers of Turkey Vultures migrating through Metchosin and East Sooke Park each Autumn are probably greater than the total breeding population on Vancouver Island. So where are these other Turkey Vultures coming from? We know that some of them are coming from the southern and northern Gulf Islands, and a few migrate across Johnstone Strait onto Northern Vancouver Island. But what about the large breeding population on the Sunshine Coast? Is it is possible that these birds somehow make their way across the Salish Sea onto Vancouver Island somehow? The distance across much of the Salish Sea is even greater than that across Jaun de Fuca Strait, and would seem to be a barrier to any of the migratory raptors that do travel well across water. Some recent observations from Moorecroft Regional Park in Nanoose, has made me wonder if perhaps the Salish Sea isn't the barrier it was previously believed to be.

On September 27th, 2011, we were doing some sea-watching from Vesper Point, in Moorecroft Regional Park. At app. 12:40, a kettle of 14 Turkey Vultures were spotted, fairly high, and north of Gerald Island. These birds were flapping hard, and seemed to be loosing altitude fairly quickly. When they reached Gerald Island, they began soaring again, and quickly gained some altitude, before soaring ashore over First Bay in Moorecroft, and then continuing on towards Nanoose Hill. About 15 minutes later, another kettle of 17 Turkey Vultures appeared app. two kilometres to the northwest, very high up and soaring towards Gerald Island. They also began catching thermals as soon as they reached Gerald Island, and it didn't take them long to reach the Moorecroft shoreline. Interestingly, this kettle also contained a Cooper's Hawk and an American Kestrel. Although I had little time today to perform active monitoring, I did notice three Turkey Vultures soaring ashore from the direction of Gerald Island.

So where are these birds coming from? The total breeding population on Gerald Island this year appeared to be one pair, and the adults and young left the island back in late August and spent several weeks in Moorecroft before going elsewhere. I would imagine that the total breeding population of the two Ballenas Islands is similar, and it is possible that they made their way onto Vancouver Island previously anyway. I can only think of two explanations. These birds are flying directly across from the Sunshine Coast (app. 28 kms) or from Lasqueti Island (app. 10 kms). I would think that direct crossing from the Sunshine Coast is unlikely. It is simply too far. Lasqueti Island is certainly within the range of a migrating Turkey Vulture though. And there are certainly more than 30 pairs of Turkey Vultures nesting on Lasqueti. How do I know this? Because for years I have counted them as they migrated from Lasqueti across to Parksville, usually coming ashore near the Englishman River Estuary, a distance of about 17 kms. The problem is, I see Turkey Vultures migrating across there every year. Why would they suddenly begin migrating in the other direction? 

I am beginning to wonder if the Turkey Vultures we have seen over the past two days are not actually from the Sunshine Coast, and are using Texada Island as a migratory Stepping Stone. Looking at a map, it becomes obvious that if Turkey Vultures do migrate between the Sunshine Coast and Vancouver Island, this is likley the route that thyey take. Using Google Earth, I made the following calculations;

Smuggler Cove (north of Sechelt) to Thormanby Island = 1.5 kms
Thormanby Island to Texada Island = 3.5 kms
Texada Island to West Ballenas Island = 12 kms
West Ballenas to Gerald Island = 3 kms
Gerald Island to Moorecroft Regional Park = 1 km   

All of this seems entirely possible for a migrating Turkey Vulture to accomplish. Now, with only about a week left in the migratory period, I need to do a lot more monitoring to see if this is indeed the case. Exactly the type of mystery that fascinates me.

Perception Vs. Reality: Altitude and Nesting Birds on Vancouver Island

Humans are funny animals. And birders, naturalists, and conservationists are no exception. Even though our knowledge of the natural world is vastly greater than the average persons, we still often miss the obvious, even when it is, well, obvious. Nowhere is this more true, than in the perceptions many birders have here on Vancouver Island, as to the altitudinal preferences of nesting birds. Dark-eyed Juncos are a good example of this, as was shown recently in a discussion on one of the local internet bird chat groups. The perception of those living in more urbanized areas, seems to be that this species prefers to nest at higher elevations, because they don't appear to nest in non-forested backyards in suburbia, but they do arrive in good numbers in Autumn, so they must be migrating down the hilsides in the winter. Is this the case? Well, yes. Sort of. And it kind of misses a point that birders spend a lot of time agitating about. That of habitat protection.

 The subspecies of Dark-eyed Junco present on most of Vancouver Island is J.h. shufeldti. It prefers to nest in forests with a certain type of canopy closure. These types of forest can occur at almost all elevations found on Vancouver Island. Thus, it is influenced far more by habitat, than it is by elevation. As can be seen using the BC Breeding Bird Atlas maps, on Vancouver Island Dark-eyed Juncos nest in most squares from the coast right through the interior areas of the island.

 

 In winter though, they tend to prefer areas with some tree cover, but larger openings. Forest edges, hedgerows, and well landscaped back yards tend to be ideal Dark-eyed Junco habitat, and these areas will host large flocks of the birds. Are all of these birds moving into these areas from higher elevations though? No. They are not.

 In autumn, numbers at lower elevations on Vancouver Island appear to increase for at least four different reasons.

1) Dark-eyed Juncos in the nesting season exist either in pairs, or in small family groups. In Autumn, they come together into much larger feeding flocks. This makes efficient counting of the birds easier. It also gives the appearance that there are more birds in the immediate area than there were in the nesting season.

2) Dark-eyed Juncos on Vancouver Island do migrate attitudinally. As snow increases at higher elevations, more and more birds move to lower elevations.

3) Dark-eyed Juncos in most of the interior of the province, as well as birds in Alaska and the Yukon, migrate south in the winter. Some of these birds will end up on Vancouver Island. These longer distance migrants likely exists in the millions, and thus the numbers on Vancouver Island should increase substantially in the Autumn and winter.

 4) As noted previously, Dark-eyed Juncos also use somewhat different habitats in winter, than they do in the nesting season. Sometimes, even at the same sites. Here in Moorecroft Regional Park, of which about 93% is covered in forest, Dark-eyed Juncos are one of the most numerous nesting birds. I have found nests from less than a meter above sea level, to the highest point in the park, which is about 60 meters. Essentially, everywhere in the park with appropriate habitat. Right now though, it is hard to find any juncos outside of the more open areas, such as parking lot and picnic area margins. And by January, it will be surprising to find any Dark-eyed Juncos at all in the park. I have no idea where these birds go in the winter. Although it is possible that they undertake some type of longer migration, my guess is that they simply move a few kilometers to where the habitat is more to their liking. It is entirely possible that the birds that nest in Moorecroft actually move up in elevation in winter, heading up the hill to areas where there has been more clearing of forests for residential developmant. Probably one of the few sites on Vancouver Island where this is the case.

 There are quite a few nesting birds on Vancouver Island that many like to equate with an altitude higher than the main urban and residential areas. The truth though, is that we come to know these birds at higher elevations, simply because this is where humans have yet to seriously alter the habitat, and we have seriously altered vast tracts of habitat along the southeast of the island . If we built our subdivisions and industrial sites above 1000 metres, and left the lowland forests intact, we might just get the idea that Sooty Grouse, Vaux's Swifts, Olive-sided Flycatchers, Steller's Jays, Hermit Thrush and Varied Thrush, were all low elevation nesters.

East Sooke Hawk Watch

Today Donna, our grandson Cedar and I headed down to East Sooke Park to take in the annual Fall migration of Turkey Vultures and raptors off of Vancouver Island. East Sooke Park is more or less the southernmost tip of Vancouver Island, and is the place where the majority of raptors, vultures, and many other migratory species, make the jump across Jaun De Fuca Strait to Washington State. Because Vultures and raptors have issues with crossing large bodies of water, the birds gather here, sometimes stacking up to counts of several thousand birds, waiting for the weather conditions to be ideal for crossing the Strait.

Today was not the best raptor watching I have ever had at East Sooke Park, but it was still exciting, and I never tire of seeing large kettles of Turkey Vultures drifting back and forth from hilltop to hilltop. The waters off East Sooke Park were also absolutely teeming with alcids and gulls today, which makes for good sea watching, when the raptor activity dies down.

We realized on the drive home that one of the reasons that the vulture count seemed low, was because there are still good numbers of them up island, which have yet to migrate. We noted 87 of them on the drive home between Metchosin and Nanoose Bay.

Birds noted between 09:00 and 14:00 today;

Turkey Vulture: 480+-
Osprey: 1
Bald Eagle: 3
Northern Harrier: 1
Sharp-shinned Hawk: 7
Cooper's Hawk: 3
Northern Goshawk: 1
Red-tailed Hawk: 29 (two dark morphs, the rest being typical western types)
Merlin: 2
Vaux's Swift: 160+-
Band-tailed Pigeon: 320+-

Loon Migration

I did a complete census of Moorecroft Regional Park this morning. I won't bore anyone with the data though. It was like a graveyard in the forest. Except for striking numbers of Red-breasted Nuthatches, there were virtually no birds at all. It did get a bit more interesting when I got to Vesper Point though. There was a really heavy migration of loons taking place. And although we have been seeing one or two Common Loons here for the past few weeks, today there were Pacific and Red-throated Loons as well. In two hours this morning I counted the following birds moving past Vesper Point;

Pacific Loon: 112
Common loon: 38
Red-throated Loon: 2

Nanoose Hill Hawk Watch

For many years I have been hoping to do some migration monitoring on local hills in the area between Nanaimo and Qualicum Beach. Unfortunately, I am usually away in the NE corner of BC at this time of year doing this type of research for wind energy project proposals. This year, with the economy in the toilet and the Canadian Conservative Party fascists dismantling the environmental assessment process, I find myself unemployed, and thus able to do a bit more hawk watching locally. Today, Donna and I hiked to the top of Nanoose Hill on what is known as the "Notch Trail". It is a quick slog to the top through Douglas Fir, Garry Oak and Arbutus forests, which are broken by rock outcrops near the top, offering great views to all directions but the east. We spent five hours here, starting at 9:00 and ending at 14:00. It was hot and sunny, with only a slight breeze from the north. Migration was slow, but we were thrilled to have as many as 23 Turkey Vultures above us at one point, soaring so close that we could hear them croaking at each other.
Birds recorded from Nanoose Hill Today:
Turkey Vulture: 66
Osprey: 1
Red-tailed Hawk: 2
Merlin: 1
Peregrine Falcon: 1
Glaucous-winged Gull: 3
California Gull: 3
Band-tailed Pigeon: 81
Vaux's Swift: 4
Anna's Hummingbird: 3
Hairy Woodpecker: 1
Northern Flicker: 10
Hammond's Flycatcher: 2
Hutton's Vireo: 3
Steller's Jay: 2
Common Raven: 12
Horned Lark: 1
Violet-green Swallow: 5
Chestnut-backed Chickadee: 14
Red-breasted Nuthatch: 27
Brown Creeper: 4
Bewick's Wren: 1
Winter Wren: 3
Golden-crowned Kinglet: 22
Ruby-crowned Kinglet: 5
Hermit Thrush: 1
American Robin: 69
Varied Thrush: 15
American Pipit: 24
Yellow-rumped Warbler: 35
Dark-eyed Junco: 21
Brewer's Blackbird: 2
Purple Finch: 3
Red Crossbill: 28
Pine Siskin: 550
American Goldfinch: 4
Evening Grosbeak: 2

Sundew Main Hawk Watch

With spectacular September weather and a day off together, Donna and I loaded the bikes on the car and drove up to the end of Sundew Rd in Nanoose Bay. We off-loaded the bikes and rode around the closed gate on the Sundew Mainlibe logging road, headed for the north flank of Siwash Ridge, about 5 kms and 500 further up the road. It was hot riding, but it only took us about 45 minutes to reach our goal, and hike the last remaining bit through every prickle and sticker bush found on Vancouver Island, to a little bare knoll where we plunked down and waited for migratory raptors to come sailing by. It was slow going this afternoon, but we stuck with it, and eventually saw 19 raptors. Not exactly like the east flank of the Rockies, but not the worst hawk-watching I have ever done on Vancouver Island. Not by a long shot.

Turkey Vulture: 16
Osprey: 1
Sharp-shinned Hawk: 1
Red-tailed Hawk: 1
Band-tailed Pigeon: 37
Rufous Hummingbird: 1 (this is getting late-ish for this species on Vancouver Island)
Steller's Jay: 2
American Robin: 88
Varied Thrush: 12
Ruby-crowned Kinglet: 1 (my first this fall)
Purple Finch: 3
American Goldfinch: 2
Pine Siskin: 205

Moorecroft Census

Today I did a complete census at Moorecroft Regional Park, in Nanoose Bay, Vancouver Island, BC. New birds for the 2012 list in the park were Common Terns, Parasitic Jaegers, and Rock Pigeon. All expected, but only seen for the first time today. Passerine migration continues to be exceedingly slow, but the number of Dark-eyed Juncos has increased substantially in the past few days. The number of Red-breasted Nuthatches locally continues to astonish. I have never seen so many in my 17 years on Vancouver Island.

Canada Goose: 3
Northern Pintail: 18
Surf Scoter: 6
Red-breasted Merganser: 2
Common Loon: 5
Brandt's Cormorant: 1
Double-crested Cormorant: 7
Pelagic Cormorant: 4
Great Blue Heron: 2
Turkey Vulture: 18
Bald Eagle: 1
Sharp-shinned Hawk: 2
Cooper's Hawk: 1
Parasitic Jaeger: 2
Bonaparte's Gull: 47
Heerman's Gull: 1
Mew Gull: 2
California Gull: 16
Glaucous-winged Gull: 31
Common Tern: 5
Rock Pigeon: 1
Barred Owl: 2
Rufous Hummingbird: 1
Anna's Hummingbird: 2
Belted Kingfisher: 2
Downy Woodpecker: 3
Hairy Woodpecker: 4
Northern Flicker: 12
Pileated Woodpecker: 4
Hutton's Vireo: 3
Common Raven: 6
Chestnut-backed Chickadee: 27
Red-breasted Nuthatch: 41
Brown Creeper: 10
Bewick's Wren: 3
Winter wren: 8
Golden-crowned Kinglet: 19
Varied Thrush: 6
American Robin: 15
American Pipit: 3
Orange-crowned Warbler: 1
Yellow-rumped Warbler: 5
Spotted Towhee: 8
Song Sparrow: 4
Dark-eyed Junco: 79
Red Crossbill: 60
Pine Siskin: 43