Differentiating North American Icteridae (1 Viewer)

[J.W.Ray]

Not a specific bird photo ID but a general one. Common Grackles, Great Tailed Grackles, Boat Tailed Grackles, and Brewer's Blackbird all occur around me. I **think** I can tell Boat Tailed apart (as they always have dark eyes?) compared to the other two grackle species, but I am unsure if I could tell the others apart. The trait differences discussed in the books I have and on the Cornell Bird site only really say bill and tail lengths differ.

Are there any other reliable visual cues to tell them apart, because from comparing lots of photos I dont think I would have as much luck telling them apart in the field.

 

[grebefeet9]

well to start with, the brewer's blackbird is considerably smaller than the other three, with a purple sheen on the head and green sheen on the body. the common grackle has a variety of iridescent colors like bronze and purple (plus it's smaller), while the gtg and btg have solid-color iridescent sheens.

 

[Tiraya]

Brewer's blackbird has a substantially shorter tail than the Grackles. Grackles are usually in pairs too, compared to those massive Brewer's flocks, save those pre-migration flocks in the winter. Blackbird vs Grackle shouldn't be much of a problem.

Great vs Boat-tailed is more of an issue, but the difference in head shape is usually fairly obvious (ish). Common should be simple to seperate on its colouration. My book suggests that where Great-t and Boat-t overlap, Boat-t always has dark eyes.

This is one of the few situations where I would say the females are easier to identify than the males.

 

[J.W.Ray]

Thanks guys.

The main reason I ask is I see people reporting all of these species from my area. I constantly see HUGE flocks of Great Tails and have been wondering lately what else might be hidden in these flocks. Ill keep my eyes out and see what I can find!

 

[Microtus]

Boat-tailed Grackles are found near the coast, not inland like in Waco. So that is one fewer species to contend with.

 

[Steve Schoech]

Grackles are usually in pairs too.

Not to be too contrary, but you need to come to Memphis where we get winter aggregations of Common Grackles. Some of the flocks and roosts are in the thousands, if not tens of thousands.

 

[csanchez7]

Boat-tailed Grackle only occurs locally along the coast in Texas. You should not be seeing them in Waco, TX.

Carlos

 

[J.W.Ray]

Yeah, boat tails really dont make it this far inland. For some reason I thought I had seen a few closer records on eBird before, but I guess I would have to drive a few hours to see them.

The flocks of grackles here in Waco have been amazingly huge as of late as well. All of the parking lots in the shopping district of town are totally filled with them come sundown, thousands of birds.

 

[Tiraya]

Not to be too contrary, but you need to come to Memphis where we get winter aggregations of Common Grackles. Some of the flocks and roosts are in the thousands, if not tens of thousands.

Hence why I said "save those pre-migration flocks in winter".

 

[csanchez7]

Grackles are usually NOT in pairs at any time of year anywhere I have birded -- even in southern California in the one location I saw Great-tailed Grackles there (near Ventura Harbor). In coastal Texas, Costa Rica, or Florida, they are a very prominent component of the avifauna of urban, suburban, and agricultural areas. They are always in large roving flocks in parking lots, parks, wetlands, or agricultural fields at all times. They breed colonially and do seem to show some variation in habitat usage throughout the year, but the social habits seem to stay the same.

Carlos

 

[grebefeet9]

i have never seen pairs of grackles either:eat: