Tag Archive | Intergrade Red-tailed Hawks

Terry’s Travels: Red-tailed Hawks, Part 2

By Terry Korolyk  

In Terry’s Travels on September 11 in the Birds Calgary Blog, I dealt with how the traditional light-phase Red-tailed Hawks of our area started to change in the new millennium  because Rufous morph and Dark morph Red-tails somehow made their way in to the local breeding stock paving the way for others of the same morph. But, not only that, the result of the breeding of mixed pairs produced intergrade Rufous or Dark morph birds with light phase birds further complicating issues by giving the defined colour morphs another outlet to push back the boundaries of local Red-tailed Hawk plumage variation.

Part 2 will deal with Dark morph Red-tailed Hawks and some unusual plumages.

Every Fall, southern Alberta is visited by northern Dark morph races of Red-tailed Hawks, and, of course, every Spring, these birds return northward. As is the case with local light phase Eastern Red-tailed Hawks being influenced by darker morph birds, northerly Dark morph birds have been intergrading more with other colour morphs including northerly light phase birds.

It seems that up to the new millenium, things were very straightforward. The darkest morph Red-tailed Hawk to come down was the Harlan’s Hawk with his blackish plumage; white-streaked breast and throat, and, mottled grayish-white tail with the dusky tip. The next basic dark morph was the Dark-morph Red-tailed Hawk with his dark brown uniform plumage with reddish tail with narrow black bars and a wider black band on the tail tip. The final basic morph was the Rufous-morph Red-tail with dark brown plumage but with a rufous-tinged breast and throat contrasting fairly sharply with the dark brown plumage. It seemed to me that variations from these basic plumages were rare at this time.

Now these morphs are not so rare, and, in the same manner that the local light-phase birds have been changing, so, have these northern races been changing. It seems that finding a pure Dark, or, Rufous morph, or, even a Harlan’s Hawk is becoming more and more difficult with each successive migration. Harlan’s Hawks in our area within the past few years seem to be showing increasingly more amounts of white with either more extensive white streaking on the underparts (or even the upperparts) and on the face. I seldom see anymore a Harlan’s Hawk with the old basic grayish-white mottled tail with the dusky tip. I can recall reading an issue of the American Birding Association’s “Birding” a few years ago that had an excellent article on Harlan’s Hawks. One page was devoted to showing the many different types of patterns Harlan’s Hawks’ tails have. Many I see in our area now seem to have some amount of red on the tail, usually in a wash on the outer half of the tail, but, with some duskiness on the tip as on this bird photographed near Longview on April 6, 2012.

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Harlan’s Red-tailed Hawk, April 6, 2012.

This bird, photographed in the hills south of Spruce Meadows Trail on October 9, 2015 is an excellent example of a recent Harlan’s Hawk with white on the face and extensive white streaking on the belly.

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Harlan’s Red-tailed Hawk, Oct. 9, 2015.

Another variation of a Harlan’s Hawk was this bird photographed on Highway 549 a few kilometres east of Highway 22 southwest of Calgary on April 6, 2012. Note the blackish plumage, but, also note the extensive unbroken white throat and breast. The tail on this bird was mottled white and had a pale reddish wash on the outer third of the tail, but, in this reddish wash was a moderately wide black subterminal band with 2 narrow wavy black bars above it.

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Harlan’s Red-tailed Hawk,  April 6, 2012.

These features made me wonder at first if, the bird might be a Harlan’s-light phase intergrade, but, there were no other redeeming features, so, I felt in the end that the bird was another variation of a Harlan’s Hawk. And, of course, there is your old basic Harlan’s Hawk with black plumage and white streaked breast such as this bird photographed on Dunbow Road just east of Highway 2 just outside Calgary City Limits on April 12, 2015.

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Harlan’s Red-tailed Hawk, April 12, 2015.

As mentioned, your basic Dark morph Red-tailed Hawk as we used to know it was a uniform dark brown. In recent years, some Dark morph birds have been labelled “vinaceous”by some birders in the United States. This term obviously implies colouration in the shade of wine referring to the colour of the breast and throat hinting at a slight contrast with the darker overall body colour. This seems reasonable to me implying a slight variation in your basic Dark morph plumage. A good example of a possible pure dark morph bird was this one photographed near Shepard near the eastern outskirts of Calgary on September 26, 2015. Although the breast can’t clearly be seen, it was definitely that of a dark morph bird; honest!

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Dark morph Red-tailed Hawk, Sept, 26, 2015.

Your basic immature dark morphs had variable amounts of white streaking on the underparts. Your immature Harlan’s Hawk would have more extensive white streaking, but would also show varying amounts of brown on the body. Your immature dark morph bird should show white streaking on the breast and throat and will also have a grayish-white tail with many narrow black bands. A good example of a dark morph immature bird is this one photographed south of Longview a few years ago.

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Immature Dark-morph Red-tailed Hawk, April 12, 2015.

Immature Rufous morph birds are similar to dark morphs, but, show more extensive streaking on the underparts covering not only the breast, but also the belly and undertail coverts. Birds of recent years seem to be showing variable amounts of white spotting on the upperparts as well. This bird photographed on 1119 Drive south of Calgary on October 13, 2012 shows the characteristics of being an immature Rufous morph Redtail. The tail is the same as on the dark morph, but, the underwings are not as heavily marked as on a dark morph bird.

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Immature Rufous morph Red-tailed Hawk, October 13, 2012.

Many of the dark morph birds that come down are intergrades, most of them seeming to be between Harlan’s and Dark, rather than Rufous. This bird, photographed during a light snowfall south of Priddis on April 7, 2013, shows much brown plumage indicating dark morph parentage. However, the expansive white breast must surely indicate Harlan’s rather than light phase parentage as there doesn’t seem to much else there that would suggest light-phase. The Ground Squirrel, of course, isn’t fussy about who the bird’s parents were.

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Dark morph/Harlan’s intergrade Red-tailed Hawk, April 7, 2013.

This is a photograph of a bird that appears to be a Harlan’s-Dark morph intergrade photographed on October 3 2014.

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Harlan’s/Dark morph intergrade Red-tailed Hawk, October 3, 2014.

A bird that I had a lot of trouble getting an identification on was a bird I photographed south of Priddis on March 20, 2013. The bird appeared to have sort of a charcoal-coloured plumage looking blackish or dusky with some brownish suffusions. There were no markings on the chest and breast, they were plain charcoal. Given those features, I thought the bird might be a candidate for Dark-morph/Harlan’s intergradation because of the mixing of the black and the brown and, the almost wholly white tail( which can be seen in the photograph) which has few indistinct blurry streaks on it. Because of the large amount of frosty edges on many of the feathers visible in the photograph and because of the white tail, I also considered the bird possibly a candidate for leucism, but, I don’t see any other supporting evidence, and, so in the end, I feel that integradation between the two is probably right. By the way, the foothills in the Priddis-Millarville-Turner Valley-Black Diamond areas are traditionally one of our best areas for seeing Raptors in migration in our area. Here is the photograph.

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Harlan’s/Dark morph intergrade Red-tailed Hawk, March 20, 2013.

Rarely, one comes across leucistic Red-tailed Hawks. I am referring to light-phase Red-tails specifically that have very few streaks on the belly and other features. I had never seen a Red-tail like that until just a few years ago. Actually, it was April 17 and 18, 2012 to be exact. On April 17, I was in the Shaw’s Meadow of Fish Creek PP in Calgary. I saw a large Hawk perched on top of a White Spruce tree on the steep south escarpment of Fish Creek. I tried to get a look at it, but couldn’t, so decided to try and take a couple of photos hoping I could identify it from the photos. I did get a couple of shots, but, it wasn’t clear what the bird was as it had its head turned and I couldn’t see the underparts.

The next day, I was in the Glennfield area of the park which is just across the road from Shaw’s Meadow. I was in luck. The bird was there, and, it was perched in the open where I could see it and get a look at it. I took three good photos of it. There were only a few barely noticeable streaks across the belly. The bird flew and I got a good look at the tail; it was white with the outer third pale red, and,  in the pale red were three black subterminal bands, the outermost one slightly wider than the other two. Since then, I have seen two other similar birds in our area, but, the three are the only ones of this ilk that I have seen since starting birding in 1987. Here is one of the Glennfield Hawk photos.

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Leucistic Light-phase Red-tailed Hawk,  April 18, 2012.

On September 27, 2015, I was birding in the hills south of Calgary. It was a beautiful Fall day, sunny and calm. I chanced upon a large Hawk that didn’t look quite right as the plumage and markings didn’t look familiar. The bird was at the 2237 Drive – 1119 Drive junction. I took a frontal shot of the bird and then one from the rear showing the tail. It was juvenile Red-tailed Hawk, but, rather than having your basic brown upperparts, they looked sort of grayish. The tail was your basic juvenile Red-tail banded tail. The frontal shot showed only a few black streaks across the belly. Here are the two shots of the bird. Considering the overall paleness of the bird, I thought it perhaps a light-phase Red-tail/Krider’s Hawk intergrade. My only other possibility would be just a variation of your light-phase Red-tailed Hawk.

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Both photos: Possible Krider’s/Light phase Red-tailed Hawk, or Light phase Red-tailed Hawk, Sept. 27, 2015.

The final bird in our account of dark-morph Red-tails and other plumages is a bird I found at Shepard on September 30, 2015. I really had never seen anything like it before as the underparts of white and black  were sort of a crazy patchwork quilt. One of the other odd things about the bird was that it had a very long scar down one side of its underbody, not unlike that of a Great Horned Owl in the August 7 story I did on those birds in the Blog. Considering the blackness of the plumage and the face of the bird, I am guessing that perhaps the bird was an immature Harlan’s Hawk, but, it flew before I could get a look at the backside of the bird. Here is the shot of that bird.

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Possible immature Harlan’s Red-tailed Hawk,  Sept. 30, 2015.

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Fall Migration; 2016

As of this date, Fall migration is really starting to ramp up in the Calgary area, Alberta’s 2nd. ever BLUE-WINGED WARBLER was reported at the Inglewood Bird Sanctuary in Calgary on September 6. The 1st. record, also at the Inglewood Bird Sanctuary, was some years ago now. A bird that may have been a JAEGER was reported to have spooked some Gulls off their roost on the shoals on the Bow River at IBS on September 6, while rare Gulls reported to this point in Calgary include an adult LESSER BLACK-BACKED GULL on the Bow River in the vicinity of the Crowchild Trail Bridge on the days of September 5th. and 6th., and, a MEW GULL, also at IBS, on September 6.

The 1st. Rough-legged Hawk of the season was reported at Two Hills on September 16, while another first, an AMERICAN GOLDEN PLOVER; a juvenile; was on the west side of Pine Coulee Reservoir west of Stavely on September 11. Birders are in luck. A HARLEQUIN DUCK has been seen at IBS already this Fall; they don’t usually show up until later in the season. A juvenile, or female, was on the river at the south end of the Sanctuary on September 12. Last year, up to 4 HARLEQUINS made it as far east as Weed Lake at Langdon in the Fall.

There have been many, many reports of BROAD-WINGED HAWKS in the Calgary area this Fall due probably, in part, to the birds appearing in areas which have intense coverage by birders. A juvenile has been seen by many birders in the Hull’s Wood and Boat Launch areas of east Fish Creek PP for about the past week. A juvenile Sharp-shinned Hawk has been hanging out in the same area for about the same length of time. Hunting must be good. Other recent Raptor reports include DARK MORPH Red-tailed Hawks, one at McElroy Slough just northeast of Chestermere Lake on September 14, then, an adult RUFOUS MORPH Red-tailed Hawk seen the next day on 64 Street south of Spruce Meadows. That makes three DARK MORPH Red-tails in our area so far this Fall season.

Up to two Peregrine Falcons have been appearing at the Marsland Basin southeast of Strathmore. The Basin is our best local hotspot for shorebirds recently with most species being reported including a recent WESTERN SANDPIPER. The Basin welcomes all birders. Go north on Range Road 242 from the Namaka Lake road and drive right in and park. There is a guest book if you wish to check in.

Bonaparte’s Gulls are starting to arrive at Chestermere Lake; this site attracts large numbers of this species in the Fall. The first SABINE’S GULLS of the Fall season were reported today, September 16. An adult and an immature bird were seen on Glenmore Reservoir by Bill Wilson. The birds are slightly late; the first arrivals usually show up by the first week in September.

There have been two recent reports of Barn Swallows still feeding young in the nest in southern Alberta. One report comes from Cooking Lake southeast of Edmonton on September 5.  Always a good indication that Fall is coming, there have been seven TOWNSEND’S SOLITAIRES reported recently in the Calgary area with Phil Quinn seeing four at the Marsland Basin on September 8. Terry Korolyk observed at least 341 American Robins move from the Millrise subdivision of Calgary to nearby Fish Creek PP, also on September 8. The day was a day with fallout conditions prevailing following a night of rainy, overcast, cool weather. Lastly for this report, a FOX SPARROW was seen at Confederation Park in northwest Calgary on September 7.

Until next time.                                                                              ——-Terry Korolyk

Terry’s Travels: Red-tailed Hawks, Part 1

By Terry Korolyk

Since starting birding in the Calgary area in 1987, I have seen many, many Red-tailed Hawks, and, have had the good fortune to be able observe the changes in the species to this point in time, 2016; 29 years. In those days, it was very straightforward; all the light-phase birds in the area were your basic Eastern Red-tail with rich rufous tails without narrow, wavy bars. Markings were fairly heavy and uniform across the belly and on the underwings. Upperparts were dark brown. The thighs were pretty well an unmarked white and the bird had the clear white throat, one of the differentiating features between Eastern Red-tails and the B.C counterpart of our bird, Buteo Jamaicensis Calurus. The patagial mark was normal and blackish. In those days, some pairs returned regularly to the same nest year after year in the Irricana Sloughs. One pair nested for many years in succession in a small grove of trees on the east side of Range Road 261 a short distance north of Township Road 262. That grove of trees is no longer there. Generally, in this area, early April saw many of the residents on territory.

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Perched Eastern Red-tailed Hawk, August 6, 2016.

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Flying Eastern Red-tail, August 6, 2016.

In the hills south of Calgary, the Eastern Red-tail ruled as well. The birds were quite common then and widespread. These days, I don’t think they are quite as common as they were then, although, they are certainly not in danger.

I moved to a new home in a different part of Calgary and I was not able to keep monitoring the Red-tails of the Irricana Sloughs as I once did. Living in the south end of the city now, however, I was able to keep track of the birds in the hills south of the city and on the prairie to the east and southeast, and, in the foothills south and southwest of the city.

On July 14, 2007, things started to change. I discovered a Dark or Rufous morph Red-tail in attendance at a nest just south of Calgary on 210 Avenue in a long east-west shelterbreak of Balsam Poplars just east of Sheriff King Street. The nest had 2 young. The bird was upset at my presence, of course, and flew around somewhat.

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Adult female Dark Morph Red-tailed Hawk, Sept.6, 2016.

I looked for the mate nearby, but, didn’t find it. Because the dark bird was the only one there and she was agitated, I guessed she was the female.

I took photographs of her and of the fledglings in the nest and one of them perched on a branch. I sent in reports to the appropriate authorities.

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Fledgling intergrade Red-tailed Hawk on branch, July 5, 2013.

I did not see that bird there the next year, but, in the year 2011, I believe it was 2011, I discovered a mixed pair, a female Rufous morph and a male light-phase bird, in Votier’s Flats in west Fish Creek PP. The birds were nesting, but, I did not see the results of that nesting. The next year, 2012, they were there again and when I went for a walk in late Summer, in 2 different locations, I could hear  large birds squawking somewhere in the underbrush as I walked  westward from the Parking Lot. I was sure those birds were probably birds fledging from the nest, although I never did see either one of them.

In 2013, the birds were there again, and, I had the good fortune to be able to get photographs of one the juveniles as it was perched on the undercarriage of a transmission tower.

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Juvenile intergrade Red-tailed Hawk, August 31, 2013.

The markings looked intermediate between those of the 2 different morphs. The male parent attended to it and brought it food as it complained, but, the Rufous morph female was nowhere to be seen.

In 2014, the pair returned, but, I didn’t have enough time to check on them that year, so, results of them being there that summer are unknown. In 2015, again, I did not have enough time to follow their progress, or, if they were even there. I think I might have glimpsed the adult female once, but, I couldn’t say for sure. In 2016, I was completely unable to see if the birds had even returned. Hopefully, 2017, I may get a chance to see if they are there.

Meanwhile, in the year, 2014, I found another mixed adult female Rufous-morph bird paired with a light-phase male Eastern Red-tail near Chestermere Lake. I was able to get photographs of the adult female.

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Adult female Rufous Morph Red-tailed Hawk, April 27, 2013.

I returned in the late Summer to see if I could see any of the young fledging. I didn’t see any, but, I did see some very unusual looking Red-tails near Weed Lake at Langdon, which is not that from Chestermere, in the Fall. Markings weren’t normal and looked like there might have been some intergradation, and, there was 1 adult Rufous morph bird on the west side of Weed Lake.

I didn’t see the birds there next year, but, that doesn’t mean they weren’t there as I was only able to check a couple of times. As a matter of fact, the birds were there again the next year, 2016, so, given that fact, I would guess the birds probably were there in 2015, they just weren’t seen. I was leading a Nature Calgary Field Trip in April this year and all the participants were able to see the birds. I wasn’t able to check to see if there were any young later in the Summer, but, we shall see if the birds return next year.

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Mixed pair of Red-tailed Hawks, April 16, 2016.

In the year 2014, I found what appeared to be a 3rd. mixed Rufous-morph–light phase pair in the hills south of Calgary southeast of Priddis. I saw both birds clearly and they were clearly a pair. I made several trips to the area through the Summer and did see the birds occasionally again. I have a good idea where the nest was located, but, did not go looking for it as, of course, they shouldn’t be disturbed. The pair were there again in 2015, but, I did not see them in 2016. However, I did come across an adult intergrade bird by itself perched in a lone tree near the Cross Conservancy south of Calgary, so, we could guess that, perhaps, the bird was a product of that relationship

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Adult intergrade Red-tailed Hawk, July 10, 2016.

The result of all this is the fact that you are seeing much more variety now in the plumage of Red-tailed Hawks in our area. You are liable to see Dark and light-phase intergrades around here now even during breeding season. To complicate things further, one must consider intergradation between Krider’s subspecies Red-tails and now, not only the Eastern Red-tail, but, also Dark morph–light phase intergrades and, even pure Rufous or Dark morph birds. So as can be seen, It is getting extremely  difficult determining exactly what sort of Red-tailed Hawk you are looking at. The Krider’s Subspecies of Red-tailed Hawk, by the way, is a whiter edition of the Eastern Red-tailed Hawk. They are more sparsely marked and the tail varies in the amount of red in the tail to some where the tail is only slightly whitish, to some where the tail shows only a faint distal blush of red.

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Krider’s Red-tailed Hawk, August 27, 2016.

To complicate things even further yet, it appears, the Mountain race of the light-phase Red-tailed Hawk , Buteo Jamaicensis Calurus, may be present in the southwest corner of the province in small numbers. The Mountain race has darker plumage, has little if any white in the throat; has black wavy bars on the red tail and has some buffiness on the upper breast and on the underwings. I have seen photographs of some birds that were in the Water Valley area northwest of Calgary , and, have encountered the bird many times in the foothills south and southwest of Calgary. I have seen photographs of some birds that were probably intergrades between itself and either Eastern Red-tail or something else, and, some of these photographs were of birds in the Irricana area and on the prairie southeast of Calgary. One must also consider a new recent classification of Red-Tailed Hawk, Buteo Jamaicensis Borealis. This is a race of light-phase Red-tail that is like the Eastern Red-tail, but has fewer markings. This race is essentially a bird of the north, hence the Latin name Borealis.

Still more on  the identification of Red-tailed Hawks in our area now, the basic juvenile Eastern Red-tailed Hawk, still has a grayish tail with several narrow, wavy blackish bars. Remainder of the markings on the birds vary with some having heavier markings than others. The belly may be sparsely streaked or it may be heavily streaked. The head may be almost completely white, or it may be quite dark. One can use that information as a barometer or measuring stick. Given all the above information, perhaps, one would be able to subsequently identify any unusally-looking juvenile Red-tailed Hawks.

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Juvenile Red-tailed Hawk, May 26, 2015.

Final item to be dealt with in regard to pale morph Red-tailed Hawks are the albinos. Albinistic birds are occasionally dealt with in our area. I have  yet to see or hear of a complete albino. These birds vary in the degree of albinism or leucism; some are almost wholly white or pale; some show only small amounts. These days almost all birds show varying amounts of white on the scapulars and other feathers. Albinism, or leucism, occurs when the amount of white or paleness present has gone out of control.

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Albino Red-tailed Hawk, July 5, 2013.

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Coming soon–Part 2 of Red-tailed Hawks in the Calgary area. Dark morphs, intergrades, and unusual plumages.

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Fall migration 2016—-

We are currently in peak period for migrating Songbirds in the Calgary area. Thus far, observer coverage has been very intensive especially at Confederation Park in northwest Calgary, and in the east side of Fish Creek Provincial Park in Calgary, particularly Mallard Point and the Boat Launch area in Hull’s Wood. The main wave of migrating Warblers and Vireos and some other Songbirds from further north has passed and now within the next couple of weeks, numbers of the second wave including American Robins, Yellow-rumped Warblers, and, Orange-crowned Warblers traditionally increases. Watch for those potential fallout conditions; overcast, cool weather, perhaps even spitting rain for large numbers and variety of birds. I live on the top floor of a Condo block in Calgary, but, we had ideal conditions the morning of Sunday, September 4 as in the ornamental trees and Trembling Aspens along the street below where we live, the trees were dripping with birds, mostly American Robins and Yellow-rumped Warblers, but, others included Red-breasted Nuthatch and I was able to get good shots of an immature Tennessee Warbler in a crab-apple tree below our balcony, and, was also able to get excellent looks at a juvenile Orange-crowned Warbler in a May Tree below our bedroom window. Palm Warblers, usually one of our later Warblers, have shown up early so far, and, a male Blackburnian Warbler has been a big draw at Confederation park starting on September 2 and was still being seen today, Labour Day, Monday, September 5.

Shorebird migration has been somewhat disappointing thus far this Fall as the July and early August rains resulted in high water levels at many waterbodies in the area. Basic early shorebird migrants like Semipalmated, Baird’s, and, Least Sandpipers should start dwindling in numbers now to the end of September. Lesser Yellowleg numbers should hold up in to October, while Greater Yellowlegs’ numbers can hold up in to early November. October is the month to watch for Black-bellied and American Golden Plovers. Pectoral Sandpipers are somewhat unpredictable. Sometimes, they are amongst the latest Fall migrants in early November.

The first rare Gull of the Fall season has been found. An adult Lesser Black-backed Gull was on the Bow River just upstream from 29 St. N.W. today, September 5. This report comes courtesy of eBird.

The first dark-morph Red-tailed Hawk of the season was just east of the Leighton Arts Centre in the hills south of Calgary on Saturday, September 3. The bird was an adult, but was a barred tail variant. I was hoping for a shot of it flying, but, 3 Swainson’s Hawks made him feel uncomfortable, and, he drifted off southward. Until next time.