This was a repeat of a raptor outing conducted on January 28th. It is interesting to contemplate the similarities and differences between the two days. To begin with, both excursions recorded 10 Northern Harriers. It appears to be a good year for them, and apparently not much has changed over a month’s time. However, the January outing recorded 19 Bald Eagles, while we had only 4 in February. My belief is that the Bald Eagles, who are preferentially piscivores (fish-eaters), wander more when Barr Lake is frozen over, as it was in January, looking to either catch such prey as rabbits or prairie dogs or to engage in kleptoparasitism, that is stealing prey from other raptors, primarily Red-tailed and Ferruginous Hawks. Note that Rough-legged Hawks, which have smaller bills and feet tend to eat smaller rodents that may not be of much interest to an eagle. With Barr Lake now having a bit more open water the Bald Eagles may not feel the need to wander as much. However, my whole theory may be completely off-base, or at least partly so, because Bald Eagles can begin migrating north as early as January, so already there may be fewer eagles in the region than a month ago.
Numbers of Red-tailed Hawks, 7 in January and 8 in February, and Rough-legged Hawks (5 and 5) were comparable between the two outings. However, there was a large difference between the number of Ferruginous Hawks (11 and 2). Some of them, as with the Bald Eagles, may have already begun moving northward, though their migration tends to occur more in March and early April. Otherwise, I’m a bit at a loss to explain why we didn’t see more this past Saturday.
Moving on to the falcons, we saw American Kestrels – 3 in January and 1 in February, Merlin (3 and 1), and Prairie Falcons (1 and 0), or a 7 to 2 decline over the past month. I believe the main explanation for this is that we also saw a decline in Horned Larks from 1092 in January to 140 in February. Nuff said. All three of these falcons are known to prey on Horned Larks. American Kestrels have been documented using abundant small birds such as Horned Larks when they are available. Merlin in winter will often specialize on locally abundant species of small birds such as Horned Larks on agricultural lands and House Sparrows around farmhouses. The area near Barr provides an abundance of these two habitats, and our Merlin on Saturday was sitting directly above a group of about sixty House Sparrows; it also had feathers in its talons. Finally, Prairie Falcons in winter feed almost exclusively on Horned Larks and Meadowlarks.
A special bonus for the day was getting to see a pair of Ring-necked Pheasants.
Good birding!
Chuck
Southeast of Barr Lake, 88th to 128th
Feb 25, 2023
21 species
11 participants
144 Canada Goose
2 Ring-necked Pheasant
150 Rock Pigeon (Feral Pigeon)
26 Eurasian Collared-Dove
10 Northern Harrier
4 Bald Eagle
8 Red-tailed Hawk
5 Rough-legged Hawk
2 Ferruginous Hawk
1 American Kestrel
1 Merlin (Prairie)
6 Black-billed Magpie
3 Black-capped Chickadee
140 Horned Lark
516 European Starling
14 American Robin
124 House Sparrow
11 House Finch
9 White-crowned Sparrow
33 Western Meadowlark
190 Red-winged Blackbird