High-Flying Birds

This chapter uses VisiData to answer this question: Which birds that are struck, on average, at the highest altitudes?

In the process, we’ll cover the following skills:

  • Assigning “types” to columns
  • Creating new columns
  • Using frequency tables to filter sheets
  • Calculating aggregate statistics

Note

If you haven’t already, download faa-wildlife-strikes.csv, a dataset of all aircraft-wildlife collisions reported to the Federal Aviation Adminsitration between 2010 and mid-2016.

Open the wildlife-strikes dataset in VisiData

Let’s start from the very beginning.

Run this command in your terminal:

vd faa-wildlife-strikes.csv

If it worked, you should see something like this:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
 OPERATOR           │ ATYPE        │ INCIDENT_DATE     │ STATE │ AIRPORT            │ PHASE_OF_FLT>
 BUSINESS           │ PA-28        │ 05/22/15 00:00:00 │ FL    │ VERO BEACH MUNICIP…│ APPROACH     │
 BUSINESS           │ BE-1900      │ 06/18/15 00:00:00 │ AK    │ KENAI MUNICIPAL AR…│ APPROACH     │
 BUSINESS           │ PA-46 MALIBU │ 09/20/15 00:00:00 │ TX    │ DAVID WAYNE HOOKS …│              │
 DELTA AIR LINES    │ B-717-200    │ 11/07/15 00:00:00 │ MO    │ LAMBERT-ST LOUIS I…│ APPROACH     │
 BUSINESS           │ BE-90 KING   │ 12/17/15 00:00:00 │ FL    │ POMPANO BEACH AIRP…│ LANDING ROLL │
 DELTA AIR LINES    │ B-757        │ 07/17/15 00:00:00 │ VI    │ HENRY E ROHLSEN AR…│              │
 DELTA AIR LINES    │ B-717-200    │ 08/02/15 00:00:00 │ TX    │ SAN ANTONIO INTL   │ APPROACH     │
 BUSINESS           │ C-414        │ 08/03/15 00:00:00 │ TX    │ LONE STAR EXECUTIV…│ DEPARTURE    │
 ALLEGIANT AIR      │ MD-80        │ 09/02/15 00:00:00 │ FL    │ TAMPA INTL         │ APPROACH     │
 TRANS STATES AIRLI…│ EMB-145      │ 09/07/15 00:00:00 │ MO    │ LAMBERT-ST LOUIS I…│ APPROACH     │
 BUSINESS           │ C-172        │ 11/28/15 00:00:00 │ FL    │ OPA-LOCKA EXECUTIV…│ APPROACH     │
 GOVERNMENT         │ EC120        │ 12/08/15 00:00:00 │ CA    │ NORMAN Y. MINETA S…│              │
 AMERICAN AIRLINES  │ A-321        │ 05/06/15 00:00:00 │ FL    │ FORT LAUDERDALE/HO…│ APPROACH     │
 EXPRESSJET AIRLINES│ CRJ100/200   │ 05/06/15 00:00:00 │ AR    │ FORT SMITH REGIONA…│ CLIMB        │
 MESA AIRLINES      │ CRJ900       │ 05/08/15 00:00:00 │ AR    │ BILL AND  HILLARY …│ LANDING ROLL │
 BUSINESS           │ HELICOPTER   │ 05/06/15 00:0┌──────────────────────────────────| statuses |─┐│
 DELTA AIR LINES    │ A-320        │ 05/07/15 00:0│ saul.pw/VisiData v3.0.2                       ││
 DELTA AIR LINES    │ A-320        │ 05/08/15 00:0│ opening datasets/faa-wildlife-strikes.csv as  ││
 LUFTHANSA          │ A-380        │ 05/10/15 00:0│ csv                                           ││
 BUSINESS           │ C-172        │ 05/08/15 00:0│ Take a breath.                                ││
 SPIRIT AIRLINES    │ A-319        │ 05/10/15 00:0└───────────────────────────────────────────────┘│
1› faa-wildlife-strikes|                                                                73448 rows 

Tell VisiData that HEIGHT is an integer column

Navigate to the HEIGHT column, and press #.

You should see something like this:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
<STATE │ AIRPORT            │ PHASE_OF_FLT │ HEIGHT#│ SPEED │ SPECIES            │ BIRDS_STRUCK │ >
 FL    │ VERO BEACH MUNICIP…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 AK    │ KENAI MUNICIPAL AR…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ DAVID WAYNE HOOKS …│              │       !│       │ Unknown bird       │ 1            │ N 
 MO    │ LAMBERT-ST LOUIS I…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 FL    │ POMPANO BEACH AIRP…│ LANDING ROLL │      0 │       │ Unknown bird       │ 1            │   
 VI    │ HENRY E ROHLSEN AR…│              │       !│       │ Unknown bird       │ 1            │ O 
 TX    │ SAN ANTONIO INTL   │ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ LONE STAR EXECUTIV…│ DEPARTURE    │       !│       │ Unknown bird       │ 1            │ P 
 FL    │ TAMPA INTL         │ APPROACH     │   6000 │       │ Unknown bird       │ 1            │ N 
 MO    │ LAMBERT-ST LOUIS I…│ APPROACH     │       !│       │ Owls               │ 1            │ N 
 FL    │ OPA-LOCKA EXECUTIV…│ APPROACH     │       !│       │ Hawks              │ 1            │ N 
 CA    │ NORMAN Y. MINETA S…│              │       !│       │ Gulls              │ 1            │ N 
 FL    │ FORT LAUDERDALE/HO…│ APPROACH     │   1500 │       │ Unknown bird - sma…│ 1            │ N 
 AR    │ FORT SMITH REGIONA…│ CLIMB        │       !│       │ Unknown bird - sma…│ 1            │ N 
 AR    │ BILL AND  HILLARY …│ LANDING ROLL │      0 │       │ Unknown bird - sma…│ 1            │ N 
       │ UNKNOWN            │ En Route     │       !│       │ Unknown bird       │ 1            │ P 
 CA    │ METRO OAKLAND INTL │              │       !│       │ Unknown bird       │ 1            │ N 
 UT    │ SALT LAKE CITY INTL│              │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ GEORGE BUSH INTERC…│ CLIMB        │       !│       │ Unknown bird       │ 1            │ N 
 FL    │ ORLANDO SANFORD IN…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 IL    │ CHICAGO O'HARE INT…│ CLIMB        │  12000 │       │ Unknown bird       │ 1            │ P 
1› faa-wildlife-strikes|                                              #   type-int      73448 rows 

As you can see, many of the reported collisions are missing height data, or appear to have occurred on the ground (i.e., HEIGHT == 0).

So, let’s focus only on collsions reported to have occurred above the ground.

Select only rows where HEIGHT is greater than zero

To do that, we’ll use z|, VisiData’s “select by expression” command. Type z| and then, at the prompt, type HEIGHT > 0. You should see something like this:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
<STATE │ AIRPORT            │ PHASE_OF_FLT │ HEIGHT#│ SPEED │ SPECIES            │ BIRDS_STRUCK │ >
 FL    │ VERO BEACH MUNICIP…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 AK    │ KENAI MUNICIPAL AR…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ DAVID WAYNE HOOKS …│              │       !│       │ Unknown bird       │ 1            │ N 
 MO    │ LAMBERT-ST LOUIS I…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 FL    │ POMPANO BEACH AIRP…│ LANDING ROLL │      0 │       │ Unknown bird       │ 1            │   
 VI    │ HENRY E ROHLSEN AR…│              │       !│       │ Unknown bird       │ 1            │ O 
 TX    │ SAN ANTONIO INTL   │ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ LONE STAR EXECUTIV…│ DEPARTURE    │       !│       │ Unknown bird       │ 1            │ P 
 FL    │ TAMPA INTL         │ APPROACH     │   6000 │       │ Unknown bird       │ 1            │ N 
 MO    │ LAMBERT-ST LOUIS I…│ APPROACH     │       !│       │ Owls               │ 1            │ N 
 FL    │ OPA-LOCKA EXECUTIV…│ APPROACH     │       !│       │ Hawks              │ 1            │ N 
 CA    │ NORMAN Y. MINETA S…│              │       !│       │ Gulls              │ 1            │ N 
 FL    │ FORT LAUDERDALE/HO…│ APPROACH     │   1500 │       │ Unknown bird - sma…│ 1            │ N 
 AR    │ FORT SMITH REGIONA…│ CLIMB        │       !│       │ Unknown bird - sma…│ 1            │ N 
 AR    │ BILL AND  HILLARY …│ LANDING ROLL │      0 │       │ Unknown bird - sma…│ 1            │ N 
       │ UNKNOWN            │ En Route     │       !│       │ Unknown bird       │ 1            │ P 
 CA    │ METRO OAKLAND INTL │              │       !│       │ Unknown bird       │ 1            │ N 
 UT    │ SALT LAKE CITY INTL│              │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ GEORGE BUSH INTERC…│ CLIMB        │       !│       │ Unknown bird       │ 1            │ N 
 FL    │ ORLANDO SANFORD IN…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 IL    │ CHICAGO O'HARE INT…│ CLIMB        │  12000 │       │ Unknown bird       │ 1            │ P 
select by expr: HEIGHT > 0                                        z|   select-expr      73448 rows 

Then press Enter. Now you you should see the above-ground collisions selected:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
<STATE │ AIRPORT            │ PHASE_OF_FLT │ HEIGHT#│ SPEED │ SPECIES            │ BIRDS_STRUCK │ >
 FL    │ VERO BEACH MUNICIP…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 AK    │ KENAI MUNICIPAL AR…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ DAVID WAYNE HOOKS …│              │       !│       │ Unknown bird       │ 1            │ N 
 MO    │ LAMBERT-ST LOUIS I…│ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 FL    │ POMPANO BEACH AIRP…│ LANDING ROLL │      0 │       │ Unknown bird       │ 1            │   
 VI    │ HENRY E ROHLSEN AR…│              │       !│       │ Unknown bird       │ 1            │ O 
 TX    │ SAN ANTONIO INTL   │ APPROACH     │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ LONE STAR EXECUTIV…│ DEPARTURE    │       !│       │ Unknown bird       │ 1            │ P 
•FL    │ TAMPA INTL         │ APPROACH     │   6000 │       │ Unknown bird       │ 1            │ N 
 MO    │ LAMBERT-ST LOUIS I…│ APPROACH     │       !│       │ Owls               │ 1            │ N 
 FL    │ OPA-LOCKA EXECUTIV…│ APPROACH     │       !│       │ Hawks              │ 1            │ N 
 CA    │ NORMAN Y. MINETA S…│              │       !│       │ Gulls              │ 1            │ N 
•FL    │ FORT LAUDERDALE/HO…│ APPROACH     │   1500 │       │ Unknown bird - sma…│ 1            │ N 
 AR    │ FORT SMITH REGIONA…│ CLIMB        │       !│       │ Unknown bird - sma…│ 1            │ N 
 AR    │ BILL AND  HILLARY …│ LANDING ROLL │      0 │       │ Unknown bird - sma…│ 1            │ N 
       │ UNKNOWN            │ En Route     │       !│       │ Unknown bird       │ 1            │ P 
 CA    │ METRO OAKLAND INTL │              │       !│       │ Unknown bird       │ 1            │ N 
 UT    │ SALT LAKE CITY INTL│              │       !│       │ Unknown bird       │ 1            │ N 
 TX    │ GEORGE BUSH INTERC…│ CLIMB        │       !│  ┌─────────────────────────────| statuses |─┐ 
 FL    │ ORLANDO SANFORD IN…│ APPROACH     │       !│  │ selected 22883 rows                      │ 
•IL    │ CHICAGO O'HARE INT…│ CLIMB        │  12000 │  └──────────────────────────────────────────┘ 
1› faa-wildlife-strikes|                                  z|   select-expr      73448 rows  •22883 

Create a new sheet with only the selected rows

To do so, press ". Once you do that, you should see something like this:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
<STATE │ AIRPORT            │ PHASE_OF_FLT │ HEIGHT#│ SPEED │ SPECIES            │ BIRDS_STRUCK │ >
 FL    │ TAMPA INTL         │ APPROACH     │   6000 │       │ Unknown bird       │ 1            │ N 
 FL    │ FORT LAUDERDALE/HO…│ APPROACH     │   1500 │       │ Unknown bird - sma…│ 1            │ N 
 IL    │ CHICAGO O'HARE INT…│ CLIMB        │  12000 │       │ Unknown bird       │ 1            │ P 
 FL    │ TAMPA INTL         │ APPROACH     │     50 │       │ Unknown bird       │ 1            │ N 
 OR    │ SOUTHWEST OREGON R…│ APPROACH     │    300 │       │ Unknown bird       │ 1            │ N 
 ME    │ PORTLAND INTL JETP…│ CLIMB        │   1000 │       │ Unknown bird       │ 1            │ N 
 VA    │ ROANOKE REGNL ARPT…│ APPROACH     │   3000 │       │ Unknown bird       │ 1            │ N 
 FL    │ MIAMI INTL         │ APPROACH     │    400 │       │ Unknown bird       │ 1            │ N 
 NY    │ SYRACUSE HANCOCK I…│ APPROACH     │    200 │       │ Unknown bird       │ 1            │ N 
       │ UNKNOWN            │ EN ROUTE     │   8000 │       │ Unknown bird       │ 1            │ P 
 PA    │ PITTSBURGH INTL AR…│ APPROACH     │   6000 │       │ Unknown bird       │ 1            │ N 
 MD    │ BALTIMORE/WASH INT…│ APPROACH     │   1000 │       │ Unknown bird       │ 1            │ N 
 NC    │ RALEIGH-DURHAM INTL│ APPROACH     │   1000 │       │ Unknown bird       │ 1            │ N 
 MI    │ WILLOW RUN ARPT    │ APPROACH     │   3000 │       │ Unknown bird - lar…│ 1            │ N 
 AK    │ TED STEVENS ANCHOR…│ APPROACH     │    100 │       │ Unknown bird       │ 1            │ N 
       │ UNKNOWN            │ LOCAL        │     80 │       │ Unknown bird       │ 1            │ N 
 DC    │ RONALD REAGAN WASH…│ APPROACH     │    100 │       │ Unknown bird       │ 1            │ N 
 AL    │ BIRMINGHAM-SHUTTLE…│ APPROACH     │   1100 │       │ Unknown bird       │ 1            │ N 
 NY    │ LA GUARDIA ARPT    │ CLIMB        │    400 │       │ Unknown bird       │ 1            │ N 
 CA    │ JOHN WAYNE-ORANGE …│ APPROACH     │   1700 │       │ Unknown bird - med…│ 1            │ N 
 FL    │ TAMPA INTL         │ APPROACH     │   1000 │       │ Unknown bird       │ 1            │ N 
2› faa-wildlife-strikes_selectedref|                                          "         22883 rows 

Get the average collision height for each species

This is a two-step process. First, navigate to the HEIGHT column, and press + to add an aggregator. At the prompt at the bottom of the screen, type mean …

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
<STATE │ AIRPORT            │ PHASE_OF_FLT │ HEIGHT#│ SPEED │ SPECIES            │ BIRDS_STRUCK │ >
 FL    │ TAMPA INTL         │ APPROACH     │   6000 │       │ Unknown bird       │ 1            │ N 
 FL    │ FORT LAUDERDALE/HO…│ APPROACH     │   1500 │       │ Unknown bird - sma…│ 1            │ N 
 IL    │ CHICAGO O'HARE INT…│ CLIMB        │  12000 │       │ Unknown bird       │ 1            │ P 
 FL    │ TAMPA INTL         │ APPROACH     │     50 │       │ Unknown bird       │ 1            │ N 
 OR    │ SOUTHWEST OREGON R…│ APPROACH     │    300 │    ┌─────────────────| Choose Aggregators |─┐ 
 ME    │ PORTLAND INTL JETP…│ CLIMB        │   1000 │    │ Start typing an aggregator name or     │ 
 VA    │ ROANOKE REGNL ARPT…│ APPROACH     │   3000 │    │ description.                           │ 
 FL    │ MIAMI INTL         │ APPROACH     │    400 │    │ Multiple aggregators can be added by   │ 
 NY    │ SYRACUSE HANCOCK I…│ APPROACH     │    200 │    │ separating spaces.                     │ 
       │ UNKNOWN            │ EN ROUTE     │   8000 │    │                                        │ 
 PA    │ PITTSBURGH INTL AR…│ APPROACH     │   6000 │    │ - Enter to select top aggregator.      │ 
                   mean - arithmetic mean of values      │ - Tab to highlight top aggregator.     │ 
                   median - median of values             │                                        │ 
                   avg - arithmetic mean of values       │ ## When Aggregator Highlighted         │ 
                   min - minimum value                   │                                        │ 
                   max - maximum value                   │ - Tab/Shift+Tab to cycle highlighted   │ 
                   mode - mode of values                 │ aggregator.                            │ 
                   sum - sum of values                   │ - Enter to select aggregators.         │ 
                   distinct - distinct values            │ - Space to add highlighted aggregator. │ 
                   count - number of values              │ - 0-9 to add numbered aggregator.      │ 
                   list - list of values                 └────────────────────────────────────────┘ 
choose aggregators: mean                                         +   aggregate-col      22883 rows 

… and then press Enter.

Note

Adding an aggregator doesn’t change the appearance of the sheet. But if you want to confirm that you’ve added an aggregator correctly, you can press Shift-C to open up the Columns Sheet, and look at the aggregators field.

Then, to get the average for each animal, navigate to the SPECIES column, and press Shift-F to create a frequency sheet. It should look something like this:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
 SPECIES            ║↓count♯│ percent%│ histogram                             ~│ HEIGHT_mean%║     
 Unknown bird       ║  2098 │    9.17 │ ■■■■■■■■■                              │            !║
 Unknown bird - sma…║  8807 │   38.49 │ ■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■ │            !║
 Unknown bird - lar…║   693 │    3.03 │ ■■                                     │            !║
 Unknown bird - med…║  3056 │   13.35 │ ■■■■■■■■■■■■■                          │            !║
 Gulls              ║   550 │    2.40 │ ■■                                     │            !║
 Northern pintail   ║    64 │    0.28 │                                        │            !║
 Barred owl         ║     3 │    0.01 │                                        │            !║
 Common raven       ║     4 │    0.02 │                                        │            !║
 Great blue heron   ║    38 │    0.17 │                                        │            !║
 American robin     ║   183 │    0.80 │                                        │            !║
 Rock pigeon        ║   219 │    0.96 │                                        │            !║
 Eastern meadowlark ║    77 │    0.34 │                                        │            !║
 Hawks              ║   131 │    0.57 │                                        │            !║
 Bald eagle         ║    42 │    0.18 │                                        │            !║
 Bonin petrel       ║     3 │    0.01 │                                        │            !║
 Killdeer           ║   199 │    0.87 │                                        │            !║
 Doves              ║    72 │    0.31 │                                        │            !║
 Turkey vulture     ║   178 │    0.78 │                                        │            !║
 Western meadowlark ║    52 │    0.23 │                                        │            !║
 Red-tailed hawk    ║   190 │    0.83 │                                        │            !║
 Rough-legged hawk  ║     6 │    0.03 │                                        │            !║
3› faa-wildlife-strikes_selectedref_SPECIES_freq|           processing… Shift+F           420 bins 

Sort the species by collision height

By default, frequency tables are sorted by the raw count of matching rows. To sort by the highest average collision height, navigate to the mean_HEIGHT column, and press ].

You should see something like this:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
 SPECIES            ║ count♯│↓HEIGHT_mean%║                                                        
 Eared grebe        ║     1 │    20000.00 ║
 Long-billed curlew ║     1 │    15000.00 ║
 Whimbrel           ║     1 │    12000.00 ║
 Lesser yellowlegs  ║     4 │     9925.00 ║
 Dusky flycatcher   ║     1 │     9500.00 ║
 Sanderling         ║     1 │     9500.00 ║
 Red-necked phalaro…║     4 │     8525.00 ║
 Clark's grebe      ║     1 │     8500.00 ║
 Northern saw-whet …║     1 │     8000.00 ║
 Grebes             ║     1 │     8000.00 ║
 Spotted sandpiper  ║     1 │     7700.00 ║
 Least flycatcher   ║     3 │     7566.67 ║
 Lark sparrow       ║     2 │     7400.00 ║
 Greater yellowlegs ║     3 │     7333.33 ║
 Pacific-slope flyc…║     3 │     7000.00 ║
 Seminole bat       ║     1 │     7000.00 ║
 Solitary sandpiper ║     2 │     6250.00 ║
 Pocketed free-tail…║     1 │     6000.00 ║
 Red-naped sapsucker║     2 │     5750.00 ║
 Cinnamon teal      ║     1 │     5600.00 ║
 Horned grebe       ║     2 │     5400.00 ║
3› faa-wildlife-strikes_selectedref_SPECIES_freq|                    ]   sort-desc        420 bins 

Hrrrm, it seems like a lot of these species show up just a few times — too few to be particularly informative. Let’s do something about that.

Limit the results to relatively common species

This step will seem familiar; it’s a lot like how we selected only above-the-ground collisions.

First, type z| to raise the “select by expression” prompt. Then, type count >= 20:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
 SPECIES            ║ count♯│↓HEIGHT_mean%║                                                        
 Eared grebe        ║     1 │    20000.00 ║
 Long-billed curlew ║     1 │    15000.00 ║
 Whimbrel           ║     1 │    12000.00 ║
 Lesser yellowlegs  ║     4 │     9925.00 ║
 Dusky flycatcher   ║     1 │     9500.00 ║
 Sanderling         ║     1 │     9500.00 ║
 Red-necked phalaro…║     4 │     8525.00 ║
 Clark's grebe      ║     1 │     8500.00 ║
 Northern saw-whet …║     1 │     8000.00 ║
 Grebes             ║     1 │     8000.00 ║
 Spotted sandpiper  ║     1 │     7700.00 ║
 Least flycatcher   ║     3 │     7566.67 ║
 Lark sparrow       ║     2 │     7400.00 ║
 Greater yellowlegs ║     3 │     7333.33 ║
 Pacific-slope flyc…║     3 │     7000.00 ║
 Seminole bat       ║     1 │     7000.00 ║
 Solitary sandpiper ║     2 │     6250.00 ║
 Pocketed free-tail…║     1 │     6000.00 ║
 Red-naped sapsucker║     2 │     5750.00 ║
 Cinnamon teal      ║     1 │     5600.00 ║
 Horned grebe       ║     2 │     5400.00 ║
select by expr: count >= 20                                       z|   select-expr        420 bins 

Next, press Enter to complete the action. Because there are no high-count species in the visible part of the sheet, you won’t notice much of effect at first; just some status messages in the sidebar:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
 SPECIES            ║ count♯│↓HEIGHT_mean%║            ┌─────────────────────────────| statuses |─┐
 Eared grebe        ║     1 │    20000.00 ║            │ selected 24 rows                         │
 Long-billed curlew ║     1 │    15000.00 ║            │ [3x] selected 56 more rows               │
 Whimbrel           ║     1 │    12000.00 ║            │ [2x] selected 34 more rows               │
 Lesser yellowlegs  ║     4 │     9925.00 ║            │ [2x] selected 49 more rows               │
 Dusky flycatcher   ║     1 │     9500.00 ║            │ [2x] selected 39 more rows               │
 Sanderling         ║     1 │     9500.00 ║            │ selected 693 more rows                   │
 Red-necked phalaro…║     4 │     8525.00 ║            │ selected 23 more rows                    │
 Clark's grebe      ║     1 │     8500.00 ║            │ selected 183 more rows                   │
 Northern saw-whet …║     1 │     8000.00 ║            │ [2x] selected 32 more rows               │
 Grebes             ║     1 │     8000.00 ║            │ selected 3056 more rows                  │
 Spotted sandpiper  ║     1 │     7700.00 ║            │ selected 2098 more rows                  │
 Least flycatcher   ║     3 │     7566.67 ║            │ selected 211 more rows                   │
 Lark sparrow       ║     2 │     7400.00 ║            │ selected 64 more rows                    │
 Greater yellowlegs ║     3 │     7333.33 ║            │ selected 53 more rows                    │
 Pacific-slope flyc…║     3 │     7000.00 ║            │ selected 43 more rows                    │
 Seminole bat       ║     1 │     7000.00 ║            │ [4x] selected 20 more rows               │
 Solitary sandpiper ║     2 │     6250.00 ║            │ [3x] selected 25 more rows               │
 Pocketed free-tail…║     1 │     6000.00 ║            │ selected 37 more rows                    │
 Red-naped sapsucker║     2 │     5750.00 ║            │ selected 60 more rows                    │
 Cinnamon teal      ║     1 │     5600.00 ║            │ [2x] selected 48 more rows               │
 Horned grebe       ║     2 │     5400.00 ║            └───| Ctrl+P to view all status messages |[┘
3› faa-wildlife-strikes_selectedref_SPECIES_freq|            z|   select-expr        420 bins  •75 

Now press " to create a new sheet containing only the selected rows. Tada!:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
 SPECIES            ║ count♯│↓HEIGHT_mean%║                                                        
 Yellow-bellied sap…║    24 │     3585.42 ║                                                        
 Swainson's thrush  ║    56 │     3454.46 ║                                                        
 Snow goose         ║    34 │     3258.82 ║                                                        
 Hermit thrush      ║    49 │     2770.10 ║                                                        
 Red-eyed vireo     ║    39 │     2768.72 ║                                                        
 Unknown bird - lar…║   693 │     2691.92 ║                                                        
 Northern shoveler  ║    23 │     2602.17 ║                                                        
 American robin     ║   183 │     2545.00 ║                                                        
 White-throated spa…║    56 │     2426.79 ║                                                        
 Greater white-fron…║    32 │     2335.94 ║                                                        
 Unknown bird - med…║  3056 │     2260.49 ║                                                        
 Unknown bird       ║  2098 │     2253.93 ║                                                        
 Dark-eyed junco    ║    39 │     2031.28 ║                                                        
 Perching birds (y) ║   211 │     2018.73 ║                                                        
 Northern pintail   ║    64 │     1980.19 ║                                                        
 American coot      ║    53 │     1965.66 ║                                                        
 Unknown bird or bat║    43 │     1892.88 ║                                                        
 Red bat            ║    20 │     1750.00 ║                                                        
 Geese              ║    56 │     1696.88 ║                                                        
 Gadwall            ║    25 │     1675.80 ║                                                        
 Gray catbird       ║    37 │     1573.27 ║                                                        
4› faa-wildlife-strikes_selectedref_SPECIES_freq_selectedref|                 "            75 bins 

Finally, type g_ to widen all the columns, so that you can read all the names:

  File  Edit  View  Column  Row  Data  Plot  System  Help     | VisiData 3.0.2 | Alt+H for help men
 SPECIES                     ║ count♯│↓HEIGHT_mean%║                                               
 Yellow-bellied sapsucker    ║    24 │     3585.42 ║                                               
 Swainson's thrush           ║    56 │     3454.46 ║                                               
 Snow goose                  ║    34 │     3258.82 ║                                               
 Hermit thrush               ║    49 │     2770.10 ║                                               
 Red-eyed vireo              ║    39 │     2768.72 ║                                               
 Unknown bird - large        ║   693 │     2691.92 ║                                               
 Northern shoveler           ║    23 │     2602.17 ║                                               
 American robin              ║   183 │     2545.00 ║                                               
 White-throated sparrow      ║    56 │     2426.79 ║                                               
 Greater white-fronted goose ║    32 │     2335.94 ║                                               
 Unknown bird - medium       ║  3056 │     2260.49 ║                                               
 Unknown bird                ║  2098 │     2253.93 ║                                               
 Dark-eyed junco             ║    39 │     2031.28 ║                                               
 Perching birds (y)          ║   211 │     2018.73 ║                                               
 Northern pintail            ║    64 │     1980.19 ║                                               
 American coot               ║    53 │     1965.66 ║                                               
 Unknown bird or bat         ║    43 │     1892.88 ║                                               
 Red bat                     ║    20 │     1750.00 ║                                               
 Geese                       ║    56 │     1696.88 ║                                               
 Gadwall                     ║    25 │     1675.80 ║                                               
 Gray catbird                ║    37 │     1573.27 ║                                               
4› faa-wildlife-strikes_selectedref_SPECIES_freq_selectedref| g_   resize-cols-max         75 bins