The world of birds is an exciting place because of all the unique aspects of widespread species and the beauties they radiate with their vibrant feathers and trademark traits.
On that note, the blue species are some of the most decorative individuals among them all due to authentic colors and captivating looks.
Of this elite group, Blue Grosbeak and Indigo Buntings are two that often perplex bird watchers with the tons of similarities they share among themselves.
My job today is to tell you how to identify the two in numerous aspects, starting from their physicality to their behavioral patterns.
You must remember that the likeness isn’t easy to tell apart without prior knowledge, so this article should be read carefully if you’re open to learn wholeheartedly.
Contents
Blue Grosbeak & Indigo Bunting Basic Stats
Some of the most basic stats on these two species are briefly discussed in this section to take you up to speed for the upcoming differentiation process!
Blue Grosbeak
Source: @mk_naturesnaps
- Scientific Name: Passerina caerulea
- Size: 14 to 19 cm (5.5 to 7.5 in)
- Locality: North and Central America
- Status: Least Concern
- Breeding Season: April to August
The species of Blue Grosbeak belongs to the “blue” clade of buntings – passerines that represent true sparrows in the world of avians. Their ‘grosbeak’ title derives from the shape of their bills that are wider than most other birds of the genera. They share the same family of Cardinalidae with Cardinal birds & contains a rich taxonomical history through the course of time.
Indigo Bunting
Source: @sean.hollow
- Scientific Name: Passerina cyanea
- Size: 11.5 to 15 cm (4.5 to 5.9 in)
- Locality: Southern Canada to northern Florida
- Status: Least Concern
- Breeding Season: May to September
Although Indigo Buntings might look similar to Blue Jays due to the similarity of feather colors, it’s actually much closer to Lazuli Buntings biologically. It falls in between the “blue” and “colored” clades of buntings by being a sister species to both groups. Experts speculated that Indigo Buntings and Blue Grosbeaks used to be of the same genera, but evolution dating back around 4 to 7 million years has paved separate paths for them.
Identifying Blue Grosbeak and Indigo Bunting
Before we head on to the later sections that discuss the traits and behaviors of these birds, identifying them with only the visuals is the first thing we should learn!
- Size: Of the two birds, Blue Grosbeak is the larger one, extending the height up to 7.5 inches at the maximum. Despite being passerines, Indigo Buntings are slightly smaller, sizing up to around 6 inches. While it might not be much out in the open, if you take close up pictures, this variance will help you in the primary identification phase.
The size difference is also reflected on their weights too. Grosbeaks are heavier, averaging at around 28 grams and Indigo Buntings here weigh around 14 grams on average. So it’s about twice as much weight that distinguishes one from the other.
- Shape: In terms of shape, Indigo Buntings have a more tighter build as opposed to Blue Grosbeaks. For the latter species, the head is somewhat flat compared to the former. Also, beaks on Indigo Buntings are leaned toward typical sparrow shape, opposing to Blue Grosbeak’s large and deep bills – especially the lower one.
- Color: Colorization stands as the major factor separating the birds. Indigo Buntings are toned more like cyan, leaving out the face with a darker shade of blue. Blue Grosbeaks on the other hand bears a vibrant blue on the back, much more defined than the other species.
That’s not all! Grosbeak’s wing feathers show stripes of whites over the black, blue and golden accent. This gold is continued on to the back part as well, only the tail remains as the exception. Indigo Bunting’s wing fringes are mostly brown & blue, and the same can be said about their tails as well.
Aspects Setting Indigo Bunting & Blue Grosbeak Apart
It’s time for us to take a closer look at the differences other than the ones that are physically present on these birds. This has more to do with regular study of patterns and analyzing them from a bird-expert’s point of view.
Source: @rayparisiphotography
Distribution Range
The distribution ranges for Indigo Buntings are quite concentrated around the central to the eastern parts of North America. From Canada to Nevada, almost all of the grounds in between host Bunting territories, even the coastal ridge of Florida is no exception. Rare occasions have marked this bird’s sighting in parts of Europe and northern South America.
Blue Grosbeak ranges are more centralized in the Americas, extending as far up to the whole of Central America. The farthest sighting for the species is eastern Ecuador but it’s not a common phenomena for them. Mostly, the range begins at the southern half of the USA with no presence in Canada.
No. of Subspecies
Blue Grosbeak species has seven recognized subspecies, the latest one in 1938. These subspecies vary very little in terms of visualization, but their nature and traits are unique to the habitats.
The seven subspecies are spreaded across the distribution range, rarely overlapping territories with one another. Indigo Buntings are one of a kind species and have no recorded or identified subspecies by ornithologists.
Migration
Both of these birds migrate partially but the patterns are indeed unique from one another. Blue Grosbeaks are year-round residents of Central America and the subsiding localities often host birds that don’t breed there. Coastal areas of the USA and Mexico are their preferred migratory zones and southern USA to the whole of Mexico stand as standard breeding grounds.
Indigo Buntings have particularly designated migratory zones. Their summer resident is mostly toward the north – southern Canada to eastern and central parts of the USA. Migration zones range over to Mexico, Central America and even South America. These birds form flocks for migration and travel during night time, arguably using stars as their guides.
Vulnerabilities
From our current lot, Indigo Buntings are known to be vulnerable to many threats in their local habitats. For instance, foxes, raccoons, snakes and even some of the predatory birds endanger these species, however, it doesn’t prevent them from increasing the population.
Additionally, louse fly parasitism also tends to harm this species at a large scale. Blue Grosbeaks aren’t safe from such predation, but it’s close to nothing compared to the other species.
Global Population
If we take the conservation status for these birds into account, neither of them are facing any imminent threat in terms of numbers across the world. But the difference in their global population should tell you which one is the safer species and is reproducing effortlessly.
Blue Grosbeaks have a global population of around 24 million individuals, that’s a convenient number to keep the bloodline running without any hiccup. However, the Indigo Bunting population is over three times more than the other one, standing at 78 million population worldwide.
Partnering
From the point of view of spending life with one partner only, none of these birds are loyal customers. Major portions of either species are indeed monogamous, but genetic traces suggest the existence of polygamy within themselves.
It’s made apparent for Blue Grosbeaks when they alter partners, or Indigo Buntings in the way that they cheat with another bird. This species takes things even further where Grosbeaks have failed to reach. They breed across species – particularly with Lazuli Buntings and produce hybridized offspring.
Vocalization
Due to being passerines, the vocalization pitch on these birds are remarkably similar. But if the pattern is broken down, you’ll be able to find hints that’ll help you nail your identification each time.
Starting off with Blue Grosbeak, the sounds it makes are more of a buzzer-type, like “bzzt”. They can be loud when threatened and the calling feels more like metals clanking together.
As opposed to it, Indigo Buntings create a buzzed “zeeep” when they’re trying to fly. Otherwise, the common pattern is more like “sweet-sweet chew-chew sweet-sweet” in high pitch. The calling sounds for each bird are given here for your convenience in identification.
Blue Grosbeak Sound
Indigo Bunting Sound
Things that are Similar in Blue Grosbeak & Indigo Bunting
Source: @upnorthlive, @rwhitehousephotography
It’s a tie between similarities and differences between the two species because they’re alike in more ways than you can think of!
Genus
Due to belonging to the same Passerina genus umbrella, a lot of the factors for the two birds are similar in many regards. For instance, despite the beak shapes being wider or narrower, there’s a resemblance in pattern in both. You’ll find further similarities because of this shared taxonomy in this section should you choose to proceed forward.
Sexual Dimorphism
Female birds for the two species are completely different from their male counterparts and resemble more with general sparrows in shape and color. Brown back feathers and lighter toned abdomen connect the two females from each of the family.
When it comes to accents, Grosbeak females have a darker and more noticeable level of black on the wing edges. For the Buntings, it’s more of a faded black leaning toward brown. This pattern and colorization is carried on to the tail. Despite such minor variances, these two look oddly similar.
Taxonomy
If we search the roots of these birds, their initial identification and documentation that comes with it, both are children of Carl Linnaeus. The birds, their genus and even family classification lays the foundation over his book Systema Naturae from 1758. There had to be extensive debates before present day classification though, which I mentioned earlier in the article.
Habitat
Even though Indigo Buntings & Blue Grosbeaks share similar habitat preferences, they rarely flock together the way one would do with their sister species. Mostly, openings at forest borders, areas with scattered trees, fields with overgrown grasses or even cultivation lands are ideal spots for these birds. It has more to do with their nesting and diet patterns along with weather.
Nesting
When it comes to nest-making, everything from the material to the nest shape are almost identical. Low trees or shrubs host the perfect nesting spots but preferable with some clearance from the ground. These are shaped like cups and built with grass, leaves and tree barks.
These passerines have found out a way to utilize spider webs as glues to knot all of it together so that the structure remains firm during incubation. Usually, the female bird from either species is the one to build, guard and incubate while the male bird collects food.
Diet
You could kind of guess from their passerine behaviors that these birds forage on the ground in search of food. Thus, they require an opening in deciduous or wooden forest to allow them this space. Even tall grasses can hamper this search, depending on the locality.
The diet chart for the two species is almost identical. These omnivorous birds consume everything between insects, berries and seeds. Winters often demand them to live off of grass seeds, but the younglings are mostly fed with insects for the nutritional value.
FAQ
Let’s clear the air a little bit more on the Blue Grosbeak vs Indigo Bunting discussion by answering a few questions asked popularly on the internet!
Q: Do Indigo Buntings and Blue Grosbeaks usually mate?
Ans: There’s no such record of Blue Grosbeak mating with an Indigo Bunting but technically speaking, it is possible and their biological resemblance would allow for hybridization. However, the more common cross-breeding practice occurs between Indigo and Blue Buntings.
Q: Are Blue Grosbeak and Indigo Buntings anything like Wrens?
Ans: There exists some degree of similarity between the two birds in question and Wrens like Carlina or House. But it’s mostly due to them belonging to the same order of Passeriformes, after which these groups diverge in family level.
Thoughts
This Indigo Bunting vs Blue Grosbeak battle has dragged on so far and delivered us information that’ll prove to be useful while dealing with their traces.
It’s not the easiest job really, to separate these two species if you haven’t mastered the factors that are key to identifying each of them.
That’s why learning about their similarities is also important, because you’ll be strolling through similar regions but be looking for different signs.
A bird-lover’s duty is to stay informed and even then it might not be enough since ornithology isn’t something that’s definitive and conclusive to the utmost degree.
So head out there, explore and witness these two beautiful birds in nature so that you can provide necessary facts that’ll aid us in understanding them even better!
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Audio Credits: xeno-canto
