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Kororā Data Analysis Report
Comprehensive analysis of Little Penguin conservation databases tracking individual birds, nests, and resightings across New Zealand beaches
Executive Summary
We have three interconnected databases tracking Little Penguin (Kororā) conservation efforts in Taranaki. These databases monitor individual birds, their nests, and resightings across two beach locations: Urenui Beach and Wai iti Beach.
Key Numbers at a Glance:
78
individual penguins
registered and tracked
42
nests
monitored across both sites
869
nest checks
conducted over 2+ years
18
resightings
of tagged birds
Database 1: Kororā ID Database (Bird Registry)
What This Database Contains
This is your master registry of individual penguins. Each row represents one penguin that has been tagged and measured. Think of it as a "birth certificate" or "passport" for each bird.
Key Information
Bird Demographics
Age Distribution:
  • Adults: 75 birds (96%)
  • Chicks: 3 birds (4%)
Sex Distribution:
  • Male: 53 birds (68%)
  • Female: 21 birds (27%)
  • Unknown: 4 birds (5%)
What Gets Measured
When a penguin is registered, researchers record:
Basic ID
Bird ID number, tag type, date/time, location
Physical measurements
Weight, bill depth, bill length, foot length, head length
Demographics
Age, sex, species
Optional
Nest ID (if found at a nest), mugshot photo, name, comments
Data Completeness Issues

⚠️ Missing Data Alert:
93.6%
Missing Nest ID
Most birds were not tagged at a nest
17%
Missing Bill Length
Some measurements not taken
85%
Missing Foot Length
Rarely measured
100%
Missing Head Length
Almost never recorded
Only 1 bird has a name — Naming is not standard practice
Database 2: Nest Checks Database (Breeding Monitoring)
What This Database Contains
This tracks nest monitoring visits over time. Each row represents one visit to a nest where researchers check on breeding activity, count eggs/chicks, and record which adult birds are present.
Key Information
Nest Status Breakdown
Attendance Patterns
When researchers visit nests, they record who's home:
Empty
367 checks (71% of recorded attendance)
Single adult
55 checks (11%)
Pair of adults
20 checks (4%)
No adults (but eggs/chicks present)
22 checks (4%)
Unknown
53 checks (10%)
Breeding Activity
Eggs:
  • Recorded in 507 checks (58% of all checks)
  • Most common: "Unknown" number (405 times) — eggs present but not counted
  • When counted: 0 eggs (76), 2 eggs (15), 1 egg (11)
Chicks:
  • Recorded in 489 checks (56% of all checks)
  • Most common: "Unknown" number (403 times) — chicks present but not counted
  • When counted: 0 chicks (67), 2 chicks (11), 1 chick (8)
Interaction Types
98%
Passive observation
849 checks — No handling
2%
Transponder scanned
19 checks — Bird ID verified
<1%
Device deployment
1 check — Equipment installed
Data Completeness Issues

⚠️ Missing Data Alert:
  • 37% missing Observer — Not always recorded who did the check
  • 41% missing Attendance — Often not recorded if adults were present
  • 95% missing Adult IDs — Rarely identify which specific birds are present
  • 98% missing Chick measurements — Weight and head length almost never recorded
Database 3: Resighting Database (Bird Observations)
What This Database Contains
This records opportunistic sightings of tagged birds outside of formal nest checks. Each row represents one observation of a tagged bird, typically when researchers spot a bird they've previously registered.
Key Information
Bird Status at Resighting
Commuting
13 observations
Bird moving between locations
Dead
3 observations
Deceased bird found
Roosting on/near nest
2 observations
Resting at nest site
Most Frequently Resighted Birds
Three birds have been resighted 3 times each:
Bird ID:
956 0000128 25471
Bird ID:
956 0000122 24628
Bird ID:
956 0000122 39990
All other birds (9 birds) have been resighted only once.
Interaction Types
  • Passive observation: 10 resightings (56%)
  • Transponder scanned: 5 resightings (28%)
  • Band read (handled): 3 resightings (17%)
Data Completeness Issues
56%
Missing Weight
Most birds not weighed during resighting
11%
Missing Location
Specific location sometimes not recorded
78%
Missing Images
Photos not always taken
How the Databases Connect
Bird ID Coverage
  • 77 birds are registered in the ID database
  • 12 birds have been resighted (all 12 are also in the ID database)
  • 65 birds have been registered but never resighted
  • 0 birds were resighted without being in the ID database
Nest Coverage
  • 3 nests appear in both the ID database and Nest Checks database
  • 39 nests appear only in the Nest Checks database
  • 0 nests appear only in the ID database
What this means: Most birds were not tagged at their nests. The nest monitoring program tracks many nests where the adult birds have not been individually tagged yet.
Adult Birds in Nest Checks
  • 8 unique adult birds are identified in the nest checks (Adult 1 or Adult 2 columns)
  • All 8 of these birds are also in the ID database
  • This represents only 10% of registered birds (8 out of 77)
What this means: Most tagged birds have not been observed at nests, or when they are at nests, they are not identified by their individual ID.
Data Quality Summary
Strengths ✓
Good temporal coverage
Data spans 2-4 years depending on database
Consistent tagging
All birds use the same Trovan 11mm transponder
Good data integrity
All resighted birds are in the ID database
Regular monitoring
869 nest checks show consistent effort
Two-site coverage
Both Urenui and Waiiti beaches monitored
Weaknesses
High proportion of "Unknown" values
Many nest checks record "Unknown" for eggs, chicks, and status
Missing observer data
37% of nest checks don't record who did the observation
Incomplete linkage
Most birds not linked to nests (93.6% missing Nest ID)
Limited morphometric data
Foot length and head length rarely measured
Low resighting rate
Only 12 birds (16% of total) have been resighted
Minimal adult identification at nests
Only 8 birds identified at nests despite 869 checks
Recommendations for Improvement
01
Standardize nest check protocols
Reduce "Unknown" entries by always counting eggs/chicks when possible
02
Improve bird-nest linkage
Record Nest ID when tagging birds at nests
03
Increase transponder scanning
Scan adults during nest checks to identify which tagged birds are breeding
04
Standardize measurements
Decide which measurements are priority and ensure they're always taken
05
Improve observer recording
Always record who conducted each nest check
06
Increase resighting effort
Consider systematic surveys to resight more tagged birds
Timeline Overview
Data Collection Periods by Database
Glossary of Terms
Kororā: Māori name for Little Penguin (Eudyptula minor)
Transponder: Electronic tag implanted in the bird that can be scanned to read a unique ID number
Trovan 11mm: A specific brand and size of transponder tag
Resighting: Observing a previously tagged bird in the field
Nest Check: A monitoring visit to a known nest site
Attendance: Whether adult birds are present at the nest during a check
Interaction Types:
  • Passive: Observation only, no handling
  • Transponder scanned: Bird ID read electronically
  • Band read (handled): Bird caught and leg band read
  • Device deployment: Equipment (camera, logger, etc.) installed
Status:
  • Breeding: Eggs or chicks present, active breeding
  • Not breeding: Nest present but no breeding activity
  • Failed: Breeding attempt unsuccessful
  • Fledged: Chick has left the nest successfully
  • Moulting: Bird replacing feathers
  • Commuting: Bird moving between locations
  • Roosting: Bird resting at a site
Visual Summary
Five visualization charts have been created to help you understand the data:
1
Bird ID Database Overview
Shows distribution by site, sex, age, and registration timeline
2
Nest Monitoring Activity
Displays nest checks over time, status, attendance, and site distribution
3
Breeding Activity Analysis
Tracks breeding checks, egg/chick counts, and most monitored nests
4
Bird Resighting Analysis
Shows resighting timeline, status, and most frequently seen birds
5
Database Integration & Coverage
Illustrates how the three databases connect and data completeness
Questions This Data Can Answer
With these three databases, we can investigate:
1. Population questions:
  • How many penguins are in the study area?
  • What is the sex ratio?
  • Are more birds at Urenui or Waiiti Beach?
2. Breeding questions:
  • Which nests are most active?
  • What is the breeding success rate?
  • When is the breeding season (based on egg/chick observations)?
  • How many eggs/chicks per nest on average?
3. Monitoring questions:
  • How often are nests checked?
  • Which nests get the most attention?
  • Are there gaps in monitoring coverage?
4. Individual bird questions:
  • Which birds have been resighted?
  • Which birds are breeding (if identified at nests)?
  • What are the physical characteristics of the population?
5. Survival questions:
  • How many tagged birds have been found dead?
  • What is the resighting rate (proxy for survival)?
Next Steps for Analysis
Breeding season analysis
Plot egg/chick observations by month to identify breeding season timing
Nest success rates
Calculate what percentage of nests with eggs successfully fledge chicks
Survival analysis
Use resighting data to estimate survival rates
Site comparison
Compare breeding success, bird size, or other metrics between Urenui and Waiiti
Individual histories
Create timelines for specific birds showing all their observations across databases
Morphometric analysis
Analyze weight, bill measurements by sex or site
Monitoring effort
Quantify observer effort and identify gaps in coverage